My son has a 2003 2500 silverado with an Allison transmission. When he was 1200 miles away from home on a job assignment the transmission all of a sudden wouldn't shift out of 1st. He had it towed to a transmission shop that had an Allison technician. They pulled codes and determined it needed a $4200 rebuilt transmission replacement. I used to be an ASE Master technician and I just couldn't believe that at 80k miles the trans was toast. So I researched the trans and came across this video. I instructed my son at to what to do and where to look. After repositioning and cleaning the plug contact pins the transmission worked flawless. Thank you so much for this video!
@@meatyklaws8774 Haters gonna hate. I'm a master and I use videos all the time. They are often better than tech data for me because listening and watching a professional sort through complicated problems lets me see what I've done already and what I might need to try. I'm ALWAYS wary about replacing modules without thorough investigation.
I have a 03 Chevy Silverado k2500. It out of nowhere stopped shifting out of 1st, speed gauge stopped working, temp gauge stopped working and so did the rpm’s gauge and had abs and parking light on and engine light. We went and changed the abs speed sensor which did not fix the problem, and then was led by people to think it was a instrument cluster. Changed out the instrument cluster, did nothing. I ran the codes on my truck and found it reading a ton of different codes but the main one being the transmission control module. I really did not want to have to buy that with how expensive it is and how expensive the cluster was but I came across this video and went out and sure as heck, one was completely unplugged!!!!! You saved me time, money, and a headache. The truck works perfect now all the gauges are reading right. And lucky me, I found the video in time and fixed it so I still have 30 days to return the instrument cluster and get my money back!!!!!
Just wanted to say that my 05 duramax started throwing tcm codes this morning and shifting into 4th gear too early so i took to the internet and found your video. You juat saved me so much time/money trying to figure that out, thank you so much sir. I found a pin short in my lower plug(clear one) and corrected it. Now my truck shifts smooth as butter again! Thank you so much!
I have to thank you immensely for this video. Saved me money and time with the dealership. Had to remove the TCU to get to water pump and it must've been enough to back the last pin on the red harness. If you were local, I'd buy you a beer!
Thanks Spartans. Two pins in my TCM connector, were pushed back. Just pulled them forward and tacked them with a spot of epoxy, on the under side of the pin. Now the transmission shifts like butter. Before the fix my 2001 GMC 2500hd 8.1L , would have to rev high to get out of first gear, then would not shift out of second gear. I had taken the TCM off to perform some maintenance, that's when they got pushed back.
Omg five shops and 2000 later this fixed my 708 code with me doing in ten mins. Cant believe not one shop knew this and seeing so many others with same issue. Please add more to title so others can find when looking up tcm problems
Great video. I got the Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner and used it on both male and female sides. Took an old tooth brush and rag to the connectors then let dry. Put it together and cleared the trans trouble code(s). Took it for a long drive and tested for codes along the way and this morning. Codes gone problem solved after years of living with the one none critical code. Thank you for sharing your knowledge and experience with us! Youd da man!
You just saved me a lot of money thanks to your RUclips knowledge my truck has reverse and 5th gear again, did exactly what you said and it works normal again🤟
So I have the same issue layed into throttle to pass and about 20secs after truck came to a hault and I pulled off the road no reverse stuck in whatever gear it was in. Check engine light came on immediately, I turned truck off back on everything was fine but felt like it wasn’t shifting right. Cleard codes changed red spin on trans filter cleaned the plug on passenger side for trans still seem a bit oddly when shifting im scared to death to even press on the gas more then I have to. I hope this works gonna try it
@@timf4292 believe it was low on tranny fluid I stayed out of my big tunes for awhile but got the itch layed into it plenty of times since and couldn’t ask for something to behave so good. I did clean the plug up too on the tranny
Had the same exact problem on my 05 GMC 3500 with Vortec 8100. Someone had replaced the lower radiator hose, and routed the wires underneath it. That caused extra strain on the harness, and pulled out a wire that had to do with torque management for the Allison 1000 and it started throwing torque management codes. Had another problem where I received the message "Range Shift Inhibited" on the display... Common problem, mine turned out to be the ignition switch. Really easy fix, and cheap. Symptoms were sometimes no gears, other times stuck in second or third, also pcm threw many trans codes... Check for power on the large white wire connected to the ignition switch... It should have power when the key is on, if not, the switch is bad. Only tool needed to change it is a flat screwdriver, did mine in the Napa parking lot. Just make sure to line up the cogs on the new switch. Has worked great ever since.
hey man I'm not sure if four yrs later you'll see this message.But my 04 dmax has been stuck in 3rd and sometimes 2nd.No reverse.Maybe every 5 or so restarts I'll have reverse.But I haven't thought of the ignition switch.you may have just saved me $5000 on a new tranny
Thank You! I replaced the fan shroud and suddenly had transmission issues. Smashed on the wiring back into the controller and boom it works. I will check the pins soon and actually fix the issue but you saved me a lot of time and money at the dealer! Thanks again!
@@tb3687 Thats good! I had to move the fan shroud a year ago to change the PS pump and I've been having a Trans Hot Engine Idle problem ever since. I've taken the pins out and cleaned them and made sure they were secure over and over with no luck. I'm so over it.
Funny how vehicle manufacturers seem to have great ideas like the L shapes pins to take the headlights out with, but then they have garbage wiring for many years having the same issues with every vehicle, and they don’t do anything to fix the problem. I bet if they gave an extra couple inches of wire and didn’t bend it so tight, that harness wouldn’t have any issues.
@@Jacobtaylor1775 Did you ever get this issue solved? I am having a similar issue where after driving for about 5 minutes the trans temp gauge will rise rapidly to 300. The dash high temp warning light will come on. This obviously isn't long enough to see that type of temp increase. Then suddenly the gauge will settle down to the normal operating temp reading and the warning light goes off. The other day after it had been sitting for a few hours, I put the key in and turned to the on position and the temp gauge showed over 200 degrees when it was absolutely cold.
Thank you for this video, I'm going crazy with all the tcm codes coming and going and thinking it's my tcm, now I will check these pins, I also removed the tcm when I replaced my radiator so I'm wondering if that was enough to pull them out, very helpful video, thank you guys
Overall, this is a very helpful video. But it took me a couple of views of your video to figure out what you meant by the red connector vs the clear connector. The clear was easy to spot. It wasn't until I recalled seeing a red plastic cover laying on the TCM that I put the connector in your hand with the red cover that you had previously removed. Now that part of the video makes sense. I still didn't see where the connectors are attached to the TCM. Right now my 2004 Itasca RV is on the shoulder of a street here in Vegas stuck in Neutral. I has a red 'Range Inhibit' and a yellow 'Transmission Fail' warning lights. It's an Allison 1000(MH?) 5-speed, Workhorse W-22, 8.1L. Maybe where the connectors are plugged in will be obvious when I return to my RV and view the TCM?
I have a 2008 Chevrolet K2500HD with an Allison 6-speed AT (MW7). The TCM has the single, 80-pin connector. We are getting a P0717 Turbine Speed Sensor Circuit No Signal code with the engine and transmission at normal operating temperature and pulling a load. The Freeze Frame data confirm that the TSS PID is ZERO when the code is set, (All the other speed sensors are normal). A previous shop has replaced the TSS, but there was no change. I get 2629Ω between PINS 20 and 80 of the TCM connector which is what I expect. No harness damage anywhere and all the pins look good. This 80-pin connector is constructed differently than your 5-speed TCM connectors, but nevertheless I checked the pins for broken locks etc.
Just watched this video, I’ll check the wiring when I get home this afternoon but I’m having an intermittent shuddering and not always downshifting smoothly. I was leaning towards torque converter but I’ll give this a shot
I see this alot with Allison 50/40 hybrid systems for transit Newflyer buses right at the inverter 24 pin wakeup connector and 32 pin A and B motor connectors. I change the female pins, the white pin holder and sub harness wiring due to corrosion right near the connectors. But towards the TCM its never an issue with the connectors because they are in the interior of transit buses.
So I've been chasing wiring issues in my 01 8.1 vortec for a couple weeks now, finally got the diagrams for modules and everything and tested A LOT of the circuits and grounds today. I was able to find a few issues that were causing problems, or would later. I thought my issues were with my TCM, allison has been going into limp mode, when this happens I'm stuck in 3rd and putting the truck into gear does not sound good at all.. but once I got to checking the PCM I found both grounds to its red connector were getting 60 ohms of resistance... I am going to double check, as I am aware this sounds outlandish especially considering some of the pins in that connector were showing over 12v... Might be a different circuit, I am not sure, but the MIL request circuit was showing around 10v. Gonna try running new grounds to PCM red connector pins 1 and 40 tomorrow, codes I've been seeing are p1781 and p1571. I'm a mechanic by trade, but vehicles have never been my forte, and electrical issues sometimes drive me crazy when I am unable to quickly solve them.
Got a tcm code and shift range inhibited as well as hard shift into reverse and sometimes drive. Just swapped the tcase. Goes through the gears (1-5) good
@riley s I changed the ignition switch and just did the internal transmission harness and plug. Still having issues with gear shifting when slowing down to about 10mph. Have codes p2610 and p2510. Been thinking it was the TCM but never have gotten the TCM code.
@Brett Fell tcase has a speed sensor in it and I blew that sensor. Also the gasket that's in between the transmission and tcase was leaking trans fluid so truck was low on fluid
hello. i’m having issues with my allison 1000. truck shifts smooth through all gears. but after driving on the freeway trans is about 170 temp. if i hit a slight bump it will lock me in 4th gear and i’ll pull off and turn truck off and on. i get a shift range inhibited code. any ideas man ?????
@Spartan Autoworx Thank you for the video. 2002 8.1 Allison 1000 harsh downshift from 3-2 and 2-1 almost like rpm increases to the point of being harsh. no codes. Seems ok in tow-haul Can you help with some advise? Thank you!
I have no down shifting and no power going uphill and high rom shifting took ti sllison techs they said no tcm signal unable comunicate to TCM they recomend TO BUY NEW TCM. to reorograned then chk if it fix problem or they go from thete once tcm comunicatiin is available. What di you think????🤔🤔
So I have a 2002 gmc sierra 2500hd duramax and I’ve pulled a p0700 code as well as p0561 & p0562 codes, so basically if I need to go into reverse I would need to shift into drive the back into reverse for the indicator to light up and the same goes for when I need to go into drive, except I need to go into 3rd then back into drive for the PRNDL to indicate I’m in drive, I’m assuming this would help solve this issue?
I got a situation on my Allison md3060, on my motorhome, a gear icon with an exclamation mark error on the dashboard and it won't go into gear. Do you think this could be a similar issue? Where would I find this control module
I hit a rough spot in the road and the 1000 allison kicks out of any gear . And i put it into neutral and back in drive and go down the road to the next big bump. Once i didn't shift out and got two codes. P0735 and p0700. Both fifth gear not in cync.
Hi, my 2002 chevy 2500 8.1l automatic w Allison will run in reverse but gets the blinking D in drive and won't move. Do you think it could be the same issue?
I have an 2002 Chevy 2500 6.0L automatic with Allison 1000 transmission. I have the same issue, transmission shifts into reverse and will move, but in Drive the 'D' blinks and it doesn't have any power to the wheel. The trans was low on fluid, 5 qts added and it's reading on the 'cold' section of the dipstick when hot and running in Park. I was hoping it was the low fluid level caused the issue but now I'll be looking at the TCM harness.
So I have a question I was running 95 and then looked down my transmission was running hot so I got it rebuilt but it is not shifting and when it does it goes in for one second then it kicks out of gear what is going on help and I checked the pins on the tcm they are all good
I have an 03 Duramax lb7 with an Allison Transmission the transmission was gone through before I bought it that's all I know was pulling a camper last week this week it has started hanging at the 3,000 RPM mark if I'm giving it fuel hard if I stay in it light it'll change just fine I watched your video and it sort of sounds like I could have that problem I've got two codes they come up first code is p 1621 and the second code is p1781 both of those are communication codes just thought I would ask for your opinion thanks in advance one of the thing I've checked my batteries and both batteries are fine my fluid level is fine in the transmission as well guess that's two things thanks again
I have 2001 Allison 5 speed Checked plugin. It looks great. How do I test if the TCM. Is bad or not. If bad what will one cost me, programmed and ready to go?
My 2003, LB seven has 200 K miles, I just had all kinds of work done to it a shift kit even and everything seems sound for the most part except for when I go over speed bumps. It does not matter 5 mph to 15 it always jumps out of gear. Any ideas on the cause
Hi I have an 04 duramax with an Allison it’s saying shift inhibited and it has all the forward gears but not reverse I am getting a scanner to look at the codes but wondering if this is the trouble or those a b solenoids
hi, I write from switzerland, my Silverado 2500 hd has a problem when it change to 4th and 5th gear, when I change I feel a big blow in the transmission, I have the error codes p0700 and p1720, also I get stuck in the 4 gear, it no longer changes in the fifth thanks a lot for the answer
Watched the video. Yes I have the same issue. Spend 2 hours getting 2 pins back up. Plastic holder was broke and I kinda fixed one pin. Is there a after market fix for this issue?
@@SpartanAutoworx Man.. You are the best.. Thank you for your site..gonna try this shortly.. as an aside.. I had my lower coolant hoses replaced a few months ago, but don't drive the truck too often.. thnx again.
Great video! I just subscribed to the channel. Do you have any recommendations for a 2018 GMC Sierra 2500 L5P that when put into reverse the "R" on the display starts blinking and the truck won't go into reverse? I just changed the TCM fuse. We are scheduled to leave town today for an event 3 hrs. away for our small business and we are stuck at the house. Trying not to panic. Any ideas to try first? EDIT- Codes being shown are P249D, P0701, P0731, P0751, P0756, P06C6
We Have a Allison transmission that only has 3 rd gear going forward. Won't shift into 1st, 2nd, 4th or 5th. Reverse is fine. We installed another transmission with low millage no change. TCM?
got offered a lly with a new trans with the 6speed i guess kit in it because it’s still the 1000 trans but it has the code p0872 and he says it’s a dirty valve body but it’s stuck i. 3rd gear and scares me lol. what do you think trans has 42k
So my trucks been shifting harder lately especially in 2 and 3 so people are saying it’s the fuel filter but I’m not sure. But could this also be the cause of it?
Trying to troubleshoot a 2005 school bus w/Allison 2000. It seems to be stuck in 3rd gear and the check trans light is on. Initially, we turned it off, turned key to on position and cycled through d-n-d-n-r-n and it came out of limp mode for a while, then went back into limp. Upon inspection, the transmission was very hot to touch (no gauge). Had a local shop try to pull codes and nothing showed up. Any help appreciated.
I have a 2000 frieghtliner fl60 ambulance with a 6 speed automatic with a push control box, it has been sitting for 3 years and now when I try to drive the truck it starts out showing 6 on the control box and doesn't shift it will display a 1 on the control box and will not go back to any other gear reverse or even back to neutral I will have to turn the truck off let it sit for a little bit started back up and then I'm able to put it back in neutral or reverse I'm hoping it's something simple, before the truck was parked the transmission did not have any issues at all
I have an 09 3500 with tha allison 1000 .it developed a shudder in low take off gears. Especially pulling a traylor. Only code it is throwing is glow plugs. Any idea if it is tyranny or not?
Just ran across your video and I have a Allison I have an 05 that is not shifting into overdrive could this have an issue in the wiring 2 has no check engine lights no service codes the only issue is it it is not shifting into overdrive appreciate any comments
All of a sudden I'm getting a hard shift into what seems like 2nd gear and I only have that gear in forward . Reverse fine . Allison 5 so 2002. Replaced NSBU ,same .
I have no com with t cm wont crank and I was checking the ground pin1 and 5 the continuity is not stable and the ohms are 50 to 300 engine ground to pin. But my power probe shows fround signal np.and my etm shows a pink wire on pin 2 that is not there?
I have an 05 lly and I am getting the range shift inhibited warning when it is cold and it wanders between in gear and not but once it warms up it is good to go.
2005 4x4 6.6 five speed had speed sensor codes and shifting issues replaced all speed sensors and scanner shows good operation. still coding speed sensor p700. Sometimes it starts out in fourth gear, sometimes stuck in 1st. also abs brake actuation. Checked both TCM connectors and found no pulled out terminals. put it back together and have a no crank. batteries are good shift indicator shows no position (not in park?).what could have happened ? now I cant even test drive to see if connections just needed cleaned ! any help out there would be awesome
Lol! It’s been awhile so I’m going to be brief. Found broken wire(s) in harness from TCM to power block. Then found broken wire to sensor in harness from power block to sensor ! Repair wires and transmission worked perfectly for about 6 months until limp mode started happening intermittently. Then found pass through plug contaminated with transmission fluid causing shift solenoid codes. Replacing plug fixed this and customer has been having no issues with transmission since then! Thanks for bringing this back as I did find several issues there! Cheers!
Hey brotha, my transmission has 42 different codes, and it did the same with 2 different transmission swaps of good transmissions. im gonna replace the internal wiring harness. Would you do this next, or what is your advice? i was thinking bad TCM, though, with the random DTCs.
two different transmissions and 42 codes on each sounds like bad tcm. We usually dont see that many pulled pins at the tcm to set codes like that. I would investigate tcm.
Hey I have a 2002 model international and i have every gear but reverse and I replace valve body speed sensor shift sensor on side ot transmission. Could this be the tcm I replaced the valve because had a stuck valve in solenoid a. Any information would be helpful thank you. Levi
I have a 06 Chevy 2500 with the 6 speed Alison replaced the tcm do to really hard shifting didn’t fix it it’s a new tranny as well could this be the issue on a 6 speed as well?
@@SpartanAutoworx ever see a 6 speed shift hard like that or any ideas? Tranny was replaced with a new one a year ago tcm is new and reprogrammed I’m at a loss
so i have an o1 gmc sierra 2500 hd w 8.1L gas and allison 1000, also have an 02 Silverado 3500 dually w LB7 and allison 1000. the Silverado has be wrecked and is a parts truck, my 2500 is my daily, yes fuel cost is horrible looking to change soon as weather permits enough work to do so. 3 days ago and 3 other times while slowing down to make a turn i get the grinding sound as if shifting a manual with out a clutch just not as loud, its a steady grind while slowing for turn my light is green but at about 20mph grinding stops much the way it did other times intermittently, i know nownits not abs pump as i never pressed it. also this time service light, im accelerating slightly out of turn, its in way too high a gear but holds it, luckily my destination part store is next turn and around to park. whole time stayed in same high gear. dignostic tool says tcm failure, short to ground, 4th gear ratio too high, and something about a solenoid, also relists some of same codes twice or more, for a total of about 10 codes. used 4 low to load onto my trailr to pull home, offloaded same and parked. will check connections soon. whats chances tcm from 02 diesel 3500 will work on 01 2500 8.1 gas. sure sbift points will be different rmps and torque converter and pressures may be different. can it be flashed to work, how much $ if i pay shipping both ways. i dont trust the local dealerships, from exp they are parts changers only.
I've got an 03 gmc with an 8.1 and allison 5 speed, I've been having an issue with starting, check engine light threw a bunch of trans codes, hard shifting, gear indicator has been working off and on, the main thing is the starting issue. Sometimes it's no crank or clicking of the relay at all, sometimes it clicks or starts to crank and then cuts out before the truck fires, I don't remember what trans codes it has threw me, but I've replaced the starter, connectors on the wiring at the starter, ignition switch all with no success. I'm going to try checking the tcm harness but is there anything else you guys would recommend?
@@SpartanAutoworx I have had the fuse box out twice to check all the wiring, I have power everywhere I need to have it in the fuse box, no corrosion, broken wires etc. And when I have no crank no start if I pull the starter relay out and jump it with a wire it turns right over.
Hi!! Where can I find the tcm on a 2014 ltz 5.3l 2wd chevy silverado 1500 ? I have a p700 code, all symptoms indicate it's faulty. I could not find it anywhere near battery or inside hood. Some say it's in the transmission itself but where I couldn't see it.
I have a couple electrical codes p0700 p0500 p0727 all sensors for electrical problems, solenoids p0748 and p0778 shifts just rough from P,R,N,D won’t come out of 1st gear Shop put in a new OEM TCM programmed and re-flashed re wired the sensors and pigtails Gave me the truck back at no cost to me and said sorry they couldn’t fix it. I changed the valve body with all new solenoids , the internal wire harness I’ve changed all the sensors out still getting the same codes I’m at a loss Will try this next
Hey there.. took the pin connector apart.. couldnt see much but after applying dielectric I had a small spark on clear pin group..for got to pull battery connections .. Now truck woult turn over.. no shift indicator but everything else works.. any ideas?
Hi I'm new at this. I have an 01 2500 HD 8100 engine with the Allison 5 speed. I get an intermittent overheat on my dash info monitor. Along with the gauge going up to 300 degrees. Checked the temp of the fluid. Also checked the cooler lines. Appx temp was 140 to 160 F degrees. Changed both filters, oil etc. Checked oil lines had no blockage. Still reads high temp. But does also drop down to normal in a second. Please help. Jim
Have the exact same problem. Replaced Manifold pressure sensor which has temp gauge inside and still have the same problem. Only happens when trans is at operating temp normally while at a stop. Really intermittent at one time it didn’t happen for over a year.
I have a 2001 Silverado 2500HD 8.1L with Allison 5 speed tranny. If I purchased a used TCM from another 2001 Chevy Silverado exactly the same as my truck, do I have to reprogram the new TCM before installing it? Do they sell the wiring harness that goes into the TCM? The clear control module was loose and the plastic piece that sits on top locking the pins in place was also loose. I did my best securing it and prevent the connecting harness from rattling. But I will see what happens and any information from you would be appreciated.'Thanks
I have a 2003 Fleetwood motorhome with a 8.1 engine and a 5 speed transmission Allison having problems with my downshift button the transmission works fine except the button stopped working doesn't downshift to 4th what could be the problem thank you
Hi, my Duramax works fine when it is cold, however after driving for 1 hour or so, then stopping, parking, then starting up and driving again, the shift indicator does not show up under the PRND3.., but will jump to the 3 when shifted to drive and it will not drive, if you let it cool for about 20-30 minutes you can get it to go into drive and go, however after driving another 45 minutes to and hour it goes into a limp mode, shifts down, over-revving the motor and then has to be cooled down before being able to drive. Is this the TCM? I took the TCM off, removed the plugs, looked for corroded plugs etc then put some dielectric grease back on and reassembled, hoever it did not fix it. What do you recommend?
im having some issues with my 05. local trans shop says its showing code for solenoid b but they just replaced solenoid b and one or 2 other solenoids and still same problem. whats the best way to contact u guys and ask a couple questions and explain what the truck is doing?
Hey man I got a 05 Lbz, with the Allison pretty sure it’s a 6 speed ? But recently it was slipping and I put stop slip in it it ran like a dream for 6 months engine recived it’s normal oil change the truck has 87,000 miles... and on its second transmisson although it was passed down to me I don’t know much about the first replacement but today it touched 200 on the gauge and started to go over just a tad and was stuck in 1st gear I pulled over turned it off and on and got back at it worked fine what would you recommend for me this shit is a pain in the ass
@@SpartanAutoworx it was at like 207 ish not really over beating but when it got hot it started slipping I put stop slip in it pretty sure I made a big mistake
2001 Chevy 3500, 8.1L gasser with the Allison 1000 5 speed. I'm getting an erratic trans temp reading on my gauge cluster. Sometimes its pegged at cold startup, sometimes it shoots from zero to 200, then creeps up and stays. Then it might drop to zero or regular operating temp, all over the place but not a twitchy gauge like these clusters sometimes exhibit. When it pegs hot, I get a "trans hot, idle engine" message and trans shifts hard, but only shifts this way while gauge is reading incorrectly. I've checked these pins you talk about and seated them all. I can't see any issues with them, no retention tabs are broke. I was able to unseat and re-seat every pin on both connectors even though none appeared loose to begin with. I checked trans harness for fluid in plug at trans, there was none. Ive checked resistance on on the pins for the temp sensor in trans and according to the specs for temperature/resistance nothing seems out of spec. Ive checked all grounds I could find, and I looked them up to make sure I didn't miss any. Including the ones on the interior near the gauge cluster under the a pillar At this point the only things I think it could be is TCM. Only caveat is it appears the previous owner/owners spliced in a shitty old security system but it did not appear to be hooked up anymore as most of the wires where just cut and Ive had no typical failing aftermarket security system issues like no starts or sudden dying etc. so Im not sure if thats contributing to the issue or if its just a distraction that needs attention later. Do you think it sounds like my TCM has failed or do you think I should keep digging at the botched wiring job under the dash for maybe a bad splice or tie in? Thanks for any help. I tried to exhaust all options I could before I asked you.
I got a question if you have the time. I push my tow button and no lights come on. I do have a edge evolution tunes on my truck. Do you think that's a button issue or a wire issue?
Could this cause multiple issues, i just bought an '01 with allison 5 speed after he fixed p0722 & p0748. Solenoid replaced but speed sensor was the real problem. I purchase and get back home about 2 hours away to it putting out p1721 so now an issue with the solenoid next to the last? Older video but hope to get a quick response wont hurt to try instead of waiting i guess. Oh and most times indicator lights blink of R and D, if it does go into gear i only got reverse and 1st, no other codes Fast update: def not apart of my problem
right now it drives great in all gears and even goes into reverse. once the transmission heats up to normal operating temp but not overheating. then you go and put it in reverse and it doesn't work. acts like its in neutral and show the range shift inhibited message??????? I changed nsbu switch, pressure switch, pc solenoid. and still same thing. Should i try a new tcm? Also i went out today and unplugged the harness from the back of the transmission. the round one, along with the connector to the nsbu switch to check wires. do i have to get a transmission relearn if you unplug these harness. I have the 2005 Allison 5 speed trans. please any help would be appreciated!!!
I'm having an issue where my truck losses reverse and when I shift into drive it slams into gear and acts like it's in 2nd or 3rd gear..service light flashing..shut it off for a bit..then it stops and I have reverse and shifts normal into drive..truck isn't drivable like this but when the service light isn't on the trans shifts great zero slip..I'm going to do what you shown hopefully it helps..was a plow truck
Hi I have a 2001 2500 duramax and it will not move when I put it in to gear. When I go back to put into park it grinds like It would if I was rolling and just through it in park. Any suggestions on what to check i have tried it in 4 lo 4 high and two while drive I really don't want to jerk the tray and transfercas out and replace if I don't half to. Any help would be great thank you
2007 Chevy 2500hd 6.0 Allison trans drives almost perfect in"D" , but when I select tow/haul mode rpms jump WAY high like over 4000rpm when I'm trying to slow down, could these connectors be the problem as well?
I have an 03, 41 transmission codes pop up and my engine won't start now, I'll double check all my pins but would a bad TCM cause a no start issue? I've checked everything, the only codes I get are transmission codes. Thanks
The truck does fine 1st 2ed and 3ed gear but want go into 4th or 5th and when it gets up to temp it try’s to slip out of gear. But it does fine for in them gears until it gets warm. What do you think could be wrong?
And I took the trans pan off and that little hole up in there where you can see the clutch’s you can move the clutch’s around a quarter of an inch so I think my clutch’s is wore out in it
I am having a check trans and range inhibited lights on an 03 international 4300 truck and it's stuck in low gear and won't shift into overdrive..notice the speedometer gauge isn't moving up.
I have a 2002 6.6 turbo diesel and every time you try to get on it she will not pass 2,500 rpm and won’t shift and hold the gear and turbo unless you take your foot off the gas and give it gas again I don’t know if the issue is the passing gear or just something wrong with the transmission in general please help!
Hey I have a 2008 Chevy Silverado 2500 hd with a 1000 Allison transmission and I have a code “p0762 shift solenoid c stuck on “ do you know how to fix it?
I have an 2005 Duramax and I was giving me a code when we put the scanner on it P0700 Transmission Control failure and P2810 pressure control solenoid G (electrical). It wouldn’t shift out if first so we changed the pressure solenoid and now it will up shift to 2nd but won’t shift out of 2nd. Also after it shift to 2nd when you put it in park or reverse it jerks real hard. I’ve been fighting this for weeks could you help me?
Is there a place to get the wiring harness to the TCM? I had a recurring PS leak and fluid deteriorated the wiring loom and I'm afraid of some wiring issues as a result. I thought maybe a new harness would help. My truck 2003 GMC Sierra 2500HD Dmax is going into limp mode because of a high transmission temp signal. I know it is electrical because it happens randomly and sometimes when I initially start the truck. I measured the temp of he trans pan with a laser thermometer and it is within op temp. For a while I could jiggle the wires going to the TCM and it would go back to normal until it happened again. I took the jacks apart and made sure the pins were properly seated and plugged it back in and I still have the same problem. I didn't have this problem at all until I changed the PS pump and had to move the TCM out of the way to take the shroud off, I'm sure it hadn't been moved since 2003... any advice would be amazing! Thanks
Jacob, Remove the connector and make sure the sockets are in place and there's no green corrosion. Reassemble. Use a tie wrap and gently pull the harness at the TCM off to the side a little. I used my pocket knife to do the same and the problem disappeared. You have a floating short that will come and go. Go slow and methodically move one thing at a time. Not too many changes at once or you'll never narrow it down. That or just carefully replace all the sockets and see if that does it.
Hey man I have a 2001 2500hd with the 8.1l v8 and it keeps on shutting off on me out of nowhere and I’ve replaced a lot on it and it still shuts off what do you think it could be
Hi this is Bob . So I just watched your video on the five speed Allison pinouts. Let me go back a little. A customer of mine was on the highway this morning at Cruise speed and all of a sudden transmission has no gears while driving. Vehicle was towed here and has no engine light no pending codes and the transmission fluid was in pretty good shape only about a quart low but it is whining in every possible gear and does not move when I put it in drive I can hear the drum or the torque converter spinning for about 20 seconds then the whining stops and drives indicator flashes. Could this have anything to do with those pinouts to the transmission control module ?
No tcm codes at all? If the PRNDL is flashing it should code out. I would check pins clear all codes and retest. I have seen allison trans code out and drop all gears. Clear codes and back to working. Usually only see this with low battery volt at start up
@@chadw9046 No. Sold the truck to someone who had a transmission and transfer case wrapped up nice and their garage that just needed a decent truck to put it in lol. Yes I cheated and took the quick and easy route and sold it.
What is the part number for this? I'm having a very hard time finding this harness. 04 duramax LLY reading code p0872, new valve body, nsbu, throttle cable. Really interested to find this harness
i HAVE A 2009 duramax (170K miles) and it throw code p0700 and p0708 and it said stabil trak service required. I had to limp it home and every once in a while i heard a clanking sound... So after researching some forums I replaced the NSBU and ignition switch. The stabil trak warning went away but the 708 code has not. it still says transmission range sensor circuit high input. Transmission fluid has been changed religiously and looks good. Could this be my problem? Should i replace the harness before the TCM? Thanks.
My 03 f650 did a unusual hard shift and check trans light came on. Truck went into a limp mode and stayed in one gear. Parked the truck for an hour or so started it up check trans light was off and shifts were normal. After about 30 minutes light came back on and went back to limp mode, could this maybe be my issue?
Wondering if anyone of you had the ECM B fuse blowing first with the original TCM? I did. Then I bought a second hand TCM and no more fuse blowing. But I've got no communication with the transmission at all. Code U2106 Keeps coming up with my cheapo scan tool. And even with my snap on Solus ultra still no communication with the transmission
Thanks for the video. I have an 03 gmc with the 5 speed allison. I have codes p0846 and p0700. It seems to start in third and stay in third. Reverse is fine. Up to this point I haven't had any problems with the transmission.
I have a 2016. duramax with allison. cooler weather now. not cold though. 40*-42. Fahrenheit. backed out of driveway and put in forward moved 10 ft and it stopped pulling and D started flashing. switched through gears and R flashes and still wont go. shut engine off 4 or 5 mind starts and goes. what could be?
having issueson 07 LBZ..... changed water pump and boom now the truck is acting all crazy.... not shifting properly . is it possible the TCM is damaged? its a 6 speed ..... is there some fix like the 5 speed i should be looking for?
2001 gmc sierra, has been throwing p0700 for two years, pulled tcm connectors, dielectric greased, no change, dropped tranny pan spun new filter on changed fluid no change. what to check next? all winter long it wont throw code once, weather gets warmer and it throws code second, third day than two weeks later(randomly throws it) when it throws it, it is only in park and the shift indicator light goes off, shut truck off, turn key on shift to drive shift back to park and restart and it is fine again code goes off until it randomly comes back on. thanks
My son has a 2003 2500 silverado with an Allison transmission. When he was 1200 miles away from home on a job assignment the transmission all of a sudden wouldn't shift out of 1st. He had it towed to a transmission shop that had an Allison technician. They pulled codes and determined it needed a $4200 rebuilt transmission replacement. I used to be an ASE Master technician and I just couldn't believe that at 80k miles the trans was toast. So I researched the trans and came across this video. I instructed my son at to what to do and where to look. After repositioning and cleaning the plug contact pins the transmission worked flawless. Thank you so much for this video!
Nice! Good job to you and author of this vid.
“Used to be a ASE master tech” BS!!! If that were true you wouldn’t need any videos
@@meatyklaws8774 haha different models different strokes.
@@meatyklaws8774 😂🤡
@@meatyklaws8774 Haters gonna hate. I'm a master and I use videos all the time. They are often better than tech data for me because listening and watching a professional sort through complicated problems lets me see what I've done already and what I might need to try. I'm ALWAYS wary about replacing modules without thorough investigation.
I have a 03 Chevy Silverado k2500. It out of nowhere stopped shifting out of 1st, speed gauge stopped working, temp gauge stopped working and so did the rpm’s gauge and had abs and parking light on and engine light. We went and changed the abs speed sensor which did not fix the problem, and then was led by people to think it was a instrument cluster. Changed out the instrument cluster, did nothing. I ran the codes on my truck and found it reading a ton of different codes but the main one being the transmission control module. I really did not want to have to buy that with how expensive it is and how expensive the cluster was but I came across this video and went out and sure as heck, one was completely unplugged!!!!! You saved me time, money, and a headache. The truck works perfect now all the gauges are reading right. And lucky me, I found the video in time and fixed it so I still have 30 days to return the instrument cluster and get my money back!!!!!
:)
Just wanted to say that my 05 duramax started throwing tcm codes this morning and shifting into 4th gear too early so i took to the internet and found your video. You juat saved me so much time/money trying to figure that out, thank you so much sir. I found a pin short in my lower plug(clear one) and corrected it. Now my truck shifts smooth as butter again! Thank you so much!
Thanks for sharing
I have to thank you immensely for this video. Saved me money and time with the dealership. Had to remove the TCU to get to water pump and it must've been enough to back the last pin on the red harness. If you were local, I'd buy you a beer!
Time for a road trip lol
Cash app him a cold one lol
Thanks Spartans. Two pins in my TCM connector, were pushed back. Just pulled them forward and tacked them with a spot of epoxy, on the under side of the pin. Now the transmission shifts like butter. Before the fix my 2001 GMC 2500hd 8.1L , would have to rev high to get out of first gear, then would not shift out of second gear. I had taken the TCM off to perform some maintenance, that's when they got pushed back.
Omg five shops and 2000 later this fixed my 708 code with me doing in ten mins. Cant believe not one shop knew this and seeing so many others with same issue. Please add more to title so others can find when looking up tcm problems
Andrew Augustine what year was your truck im having trouble getting to the pins on mine its a 2011 6 speed
Trust me the shops know all about this. No money in fixing the actual problem but they can bilk you for all kinds of $$ "trying" to fix it.
Great video. I got the Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner and used it on both male and female sides. Took an old tooth brush and rag to the connectors then let dry. Put it together and cleared the trans trouble code(s). Took it for a long drive and tested for codes along the way and this morning. Codes gone problem solved after years of living with the one none critical code. Thank you for sharing your knowledge and experience with us! Youd da man!
You just saved me a lot of money thanks to your RUclips knowledge my truck has reverse and 5th gear again, did exactly what you said and it works normal again🤟
Glad I could help
So I have the same issue layed into throttle to pass and about 20secs after truck came to a hault and I pulled off the road no reverse stuck in whatever gear it was in. Check engine light came on immediately, I turned truck off back on everything was fine but felt like it wasn’t shifting right. Cleard codes changed red spin on trans filter cleaned the plug on passenger side for trans still seem a bit oddly when shifting im scared to death to even press on the gas more then I have to. I hope this works gonna try it
@@chrismalone4491I have the same issue with my duramax. Did you find the problem?
@@timf4292 believe it was low on tranny fluid I stayed out of my big tunes for awhile but got the itch layed into it plenty of times since and couldn’t ask for something to behave so good. I did clean the plug up too on the tranny
I was just about to replace my TCM 5 speed and I will check this first. Thank you thank you. God bless you.
Good luck!
Had the same exact problem on my 05 GMC 3500 with Vortec 8100. Someone had replaced the lower radiator hose, and routed the wires underneath it. That caused extra strain on the harness, and pulled out a wire that had to do with torque management for the Allison 1000 and it started throwing torque management codes. Had another problem where I received the message "Range Shift Inhibited" on the display... Common problem, mine turned out to be the ignition switch. Really easy fix, and cheap. Symptoms were sometimes no gears, other times stuck in second or third, also pcm threw many trans codes... Check for power on the large white wire connected to the ignition switch... It should have power when the key is on, if not, the switch is bad. Only tool needed to change it is a flat screwdriver, did mine in the Napa parking lot. Just make sure to line up the cogs on the new switch. Has worked great ever since.
hey man I'm not sure if four yrs later you'll see this message.But my 04 dmax has been stuck in 3rd and sometimes 2nd.No reverse.Maybe every 5 or so restarts I'll have reverse.But I haven't thought of the ignition switch.you may have just saved me $5000 on a new tranny
@@Grannypannies Worth a try for sure. If not holler back at me, there are some other things to check.
Did u ever fix it
@@MoeDog-sy5dj Yes - has been working fine for a long time. Are you having a similar issue?
Thanks a lot .I don’t usually comment but this video saved me a lot of time and money. This was my exact issue. I’m back on the road. Thanks again
Always happy to hear when customers get it fixed. 😎
Thank You! I replaced the fan shroud and suddenly had transmission issues. Smashed on the wiring back into the controller and boom it works. I will check the pins soon and actually fix the issue but you saved me a lot of time and money at the dealer! Thanks again!
Did it work?
Yes. Haven’t had an issue since. It’s been a few months now with no issues since.
@@tb3687 Thats good! I had to move the fan shroud a year ago to change the PS pump and I've been having a Trans Hot Engine Idle problem ever since. I've taken the pins out and cleaned them and made sure they were secure over and over with no luck. I'm so over it.
Funny how vehicle manufacturers seem to have great ideas like the L shapes pins to take the headlights out with, but then they have garbage wiring for many years having the same issues with every vehicle, and they don’t do anything to fix the problem.
I bet if they gave an extra couple inches of wire and didn’t bend it so tight, that harness wouldn’t have any issues.
@@Jacobtaylor1775 Did you ever get this issue solved? I am having a similar issue where after driving for about 5 minutes the trans temp gauge will rise rapidly to 300. The dash high temp warning light will come on. This obviously isn't long enough to see that type of temp increase. Then suddenly the gauge will settle down to the normal operating temp reading and the warning light goes off. The other day after it had been sitting for a few hours, I put the key in and turned to the on position and the temp gauge showed over 200 degrees when it was absolutely cold.
Man this worked saved me a trouble and money. Thanks again keeping another Allison on the road.
No problem 👍
Badass video!! Perfect fix for my truck issues today! Thank you.
Thank you for this video, I'm going crazy with all the tcm codes coming and going and thinking it's my tcm, now I will check these pins, I also removed the tcm when I replaced my radiator so I'm wondering if that was enough to pull them out, very helpful video, thank you guys
Very informative video and not staged -- like that the mud dauber nest is still on the controller.
I’m gonna have to go watch and see now lol hopefully I knocked the nest off before I reinstalled it lol
Overall, this is a very helpful video.
But it took me a couple of views of your video to figure out what you meant by the red connector vs the clear connector. The clear was easy to spot. It wasn't until I recalled seeing a red plastic cover laying on the TCM that I put the connector in your hand with the red cover that you had previously removed. Now that part of the video makes sense.
I still didn't see where the connectors are attached to the TCM. Right now my 2004 Itasca RV is on the shoulder of a street here in Vegas stuck in Neutral. I has a red 'Range Inhibit' and a yellow 'Transmission Fail' warning lights. It's an Allison 1000(MH?) 5-speed, Workhorse W-22, 8.1L. Maybe where the connectors are plugged in will be obvious when I return to my RV and view the TCM?
I have a 2008 Chevrolet K2500HD with an Allison 6-speed AT (MW7). The TCM has the single, 80-pin connector. We are getting a P0717 Turbine Speed Sensor Circuit No Signal code with the engine and transmission at normal operating temperature and pulling a load. The Freeze Frame data confirm that the TSS PID is ZERO when the code is set, (All the other speed sensors are normal). A previous shop has replaced the TSS, but there was no change. I get 2629Ω between PINS 20 and 80 of the TCM connector which is what I expect. No harness damage anywhere and all the pins look good. This 80-pin connector is constructed differently than your 5-speed TCM connectors, but nevertheless I checked the pins for broken locks etc.
On a six speed no need to diagnose it’s always the transmission control module lol 😂
Just watched this video, I’ll check the wiring when I get home this afternoon but I’m having an intermittent shuddering and not always downshifting smoothly. I was leaning towards torque converter but I’ll give this a shot
Probably converter
Do a torque converter rpm test
I see this alot with Allison 50/40 hybrid systems for transit Newflyer buses right at the inverter 24 pin wakeup connector and 32 pin A and B motor connectors. I change the female pins, the white pin holder and sub harness wiring due to corrosion right near the connectors. But towards the TCM its never an issue with the connectors because they are in the interior of transit buses.
So I've been chasing wiring issues in my 01 8.1 vortec for a couple weeks now, finally got the diagrams for modules and everything and tested A LOT of the circuits and grounds today. I was able to find a few issues that were causing problems, or would later. I thought my issues were with my TCM, allison has been going into limp mode, when this happens I'm stuck in 3rd and putting the truck into gear does not sound good at all.. but once I got to checking the PCM I found both grounds to its red connector were getting 60 ohms of resistance... I am going to double check, as I am aware this sounds outlandish especially considering some of the pins in that connector were showing over 12v... Might be a different circuit, I am not sure, but the MIL request circuit was showing around 10v. Gonna try running new grounds to PCM red connector pins 1 and 40 tomorrow, codes I've been seeing are p1781 and p1571. I'm a mechanic by trade, but vehicles have never been my forte, and electrical issues sometimes drive me crazy when I am unable to quickly solve them.
Thanks for the great video and great customer service to boot!
Got a tcm code and shift range inhibited as well as hard shift into reverse and sometimes drive. Just swapped the tcase. Goes through the gears (1-5) good
Truck still working good?
@@brettfell551 yep had to clean the main connector to trans. (Fills with trans fluid) also ignition switch to be safe
@riley s I changed the ignition switch and just did the internal transmission harness and plug. Still having issues with gear shifting when slowing down to about 10mph. Have codes p2610 and p2510. Been thinking it was the TCM but never have gotten the TCM code.
@riley s changing the transfer case stopped the shift range inhibited and intermittent gear shifting for you?
@Brett Fell tcase has a speed sensor in it and I blew that sensor. Also the gasket that's in between the transmission and tcase was leaking trans fluid so truck was low on fluid
hello. i’m having issues with my allison 1000. truck shifts smooth through all gears. but after driving on the freeway trans is about 170 temp. if i hit a slight bump it will lock me in 4th gear and i’ll pull off and turn truck off and on. i get a shift range inhibited code. any ideas man ?????
I’m having the exact same issues let me know if you get yours fixed
@Spartan Autoworx Thank you for the video. 2002 8.1 Allison 1000 harsh downshift from 3-2 and 2-1 almost like rpm increases to the point of being harsh. no codes. Seems ok in tow-haul Can you help with some advise? Thank you!
Wish I saw this before a 8K rebuild, and 2500 dollars suncoast 6 speed conversion. FACEPALM. ugh. Thanks for the video.
I have no down shifting and no power going uphill and high rom shifting took ti sllison techs they said no tcm signal unable comunicate to TCM they recomend TO BUY NEW TCM. to reorograned then chk if it fix problem or they go from thete once tcm comunicatiin is available. What di you think????🤔🤔
Ansame?
What year?
So I have a 2002 gmc sierra 2500hd duramax and I’ve pulled a p0700 code as well as p0561 & p0562 codes, so basically if I need to go into reverse I would need to shift into drive the back into reverse for the indicator to light up and the same goes for when I need to go into drive, except I need to go into 3rd then back into drive for the PRNDL to indicate I’m in drive, I’m assuming this would help solve this issue?
I got a situation on my Allison md3060, on my motorhome, a gear icon with an exclamation mark error on the dashboard and it won't go into gear. Do you think this could be a similar issue? Where would I find this control module
I hit a rough spot in the road and the 1000 allison kicks out of any gear .
And i put it into neutral and back in drive and go down the road to the next big bump.
Once i didn't shift out and got two codes.
P0735 and p0700.
Both fifth gear not in cync.
Hi, my 2002 chevy 2500 8.1l automatic w Allison will run in reverse but gets the blinking D in drive and won't move. Do you think it could be the same issue?
I have an 2002 Chevy 2500 6.0L automatic with Allison 1000 transmission.
I have the same issue, transmission shifts into reverse and will move, but in Drive the 'D' blinks and it doesn't have any power to the wheel.
The trans was low on fluid, 5 qts added and it's reading on the 'cold' section of the dipstick when hot and running in Park.
I was hoping it was the low fluid level caused the issue but now I'll be looking at the TCM harness.
Checking my pins today. As when cold shifts hard from 1st to 2nd once warmed up truck shifts perfect. Ideas?
Mine is similar. I have to let my truck warm up and transmission get to atleast 70+ degrees before I can successfully clear codes for it to shift.
Thanks for the advise. I should have checked the connector after doing my voltage and ground checks.
So I have a question I was running 95 and then looked down my transmission was running hot so I got it rebuilt but it is not shifting and when it does it goes in for one second then it kicks out of gear what is going on help and I checked the pins on the tcm they are all good
I have an 03 Duramax lb7 with an Allison Transmission the transmission was gone through before I bought it that's all I know was pulling a camper last week this week it has started hanging at the 3,000 RPM mark if I'm giving it fuel hard if I stay in it light it'll change just fine I watched your video and it sort of sounds like I could have that problem I've got two codes they come up first code is p 1621 and the second code is p1781 both of those are communication codes just thought I would ask for your opinion thanks in advance one of the thing I've checked my batteries and both batteries are fine my fluid level is fine in the transmission as well guess that's two things thanks again
I have 2001 Allison 5 speed
Checked plugin. It looks great.
How do I test if the TCM. Is bad or not.
If bad what will one cost me, programmed and ready to go?
What was your problems? Did your truck have no drive or reverse?
My 2003, LB seven has 200 K miles, I just had all kinds of work done to it a shift kit even and everything seems sound for the most part except for when I go over speed bumps. It does not matter 5 mph to 15 it always jumps out of gear. Any ideas on the cause
My truck threw a p0732 code incorrect gear ratio along with a p0700 5 speed Allison what’s your thoughts
My truck just threw the same codes when going up hill and I accelerated hard. What was the upcome of your problem?
Can a feller buy this harness brand new?
Hi I have an 04 duramax with an Allison it’s saying shift inhibited and it has all the forward gears but not reverse I am getting a scanner to look at the codes but wondering if this is the trouble or those a b solenoids
hi, I write from switzerland, my Silverado 2500 hd has a problem when it change to 4th and 5th gear, when I change I feel a big blow in the transmission, I have the error codes p0700 and p1720, also I get stuck in the 4 gear, it no longer changes in the fifth
thanks a lot for the answer
Watched the video. Yes I have the same issue. Spend 2 hours getting 2 pins back up. Plastic holder was broke and I kinda fixed one pin. Is there a after market fix for this issue?
Not aftermarket we can sell you a bare connector
have you done a vid on the repair of the pins?.. especially the brittle plastic ones.. Do you just use pliers to pull the pin back into place?
I do not. You can push and pull the pins by hand.
@@SpartanAutoworx Man.. You are the best.. Thank you for your site..gonna try this shortly.. as an aside.. I had my lower coolant hoses replaced a few months ago, but don't drive the truck too often.. thnx again.
I have a 07 duramax , getting codes p0700,0877 and 0848, transmission going in to limp mode continuously. Any Idea?
Great video! I just subscribed to the channel. Do you have any recommendations for a 2018 GMC Sierra 2500 L5P that when put into reverse the "R" on the display starts blinking and the truck won't go into reverse? I just changed the TCM fuse. We are scheduled to leave town today for an event 3 hrs. away for our small business and we are stuck at the house. Trying not to panic. Any ideas to try first?
EDIT- Codes being shown are P249D, P0701, P0731, P0751, P0756, P06C6
Bad tcm
We Have a Allison transmission that only has 3 rd gear going forward. Won't shift into 1st, 2nd, 4th or 5th. Reverse is fine. We installed another transmission with low millage no change. TCM?
got offered a lly with a new trans with the 6speed i guess kit in it because it’s still the 1000 trans but it has the code p0872 and he says it’s a dirty valve body but it’s stuck i. 3rd gear and scares me lol. what do you think trans has 42k
So my trucks been shifting harder lately especially in 2 and 3 so people are saying it’s the fuel filter but I’m not sure. But could this also be the cause of it?
Codes? Doubtful it’s filter
Trying to troubleshoot a 2005 school bus w/Allison 2000. It seems to be stuck in 3rd gear and the check trans light is on. Initially, we turned it off, turned key to on position and cycled through d-n-d-n-r-n and it came out of limp mode for a while, then went back into limp. Upon inspection, the transmission was very hot to touch (no gauge). Had a local shop try to pull codes and nothing showed up. Any help appreciated.
So no history codes or can you get codes pulled while its not wanting to play nice?
You're awesome!! Thank you!!
Mike Fitzgerald
Calgary Canada 🇨🇦
Thanks for watching!
I have a 2000 frieghtliner fl60 ambulance with a 6 speed automatic with a push control box, it has been sitting for 3 years and now when I try to drive the truck it starts out showing 6 on the control box and doesn't shift it will display a 1 on the control box and will not go back to any other gear reverse or even back to neutral I will have to turn the truck off let it sit for a little bit started back up and then I'm able to put it back in neutral or reverse I'm hoping it's something simple, before the truck was parked the transmission did not have any issues at all
Allison 6 speed transmission? if so bad tcm hands down
@@SpartanAutoworx yes it's a 6 speed transmission automatic with push button box gear control
I have an 09 3500 with tha allison 1000 .it developed a shudder in low take off gears. Especially pulling a traylor. Only code it is throwing is glow plugs. Any idea if it is tyranny or not?
Converter maybe
Just ran across your video and I have a Allison I have an 05 that is not shifting into overdrive could this have an issue in the wiring 2 has no check engine lights no service codes the only issue is it it is not shifting into overdrive appreciate any comments
Could be
All of a sudden I'm getting a hard shift into what seems like 2nd gear and I only have that gear in forward . Reverse fine . Allison 5 so 2002. Replaced NSBU ,same .
Any codes?
I have no com with t cm wont crank and I was checking the ground pin1 and 5 the continuity is not stable and the ohms are 50 to 300 engine ground to pin. But my power probe shows fround signal np.and my etm shows a pink wire on pin 2 that is not there?
I have an 05 lly and I am getting the range shift inhibited warning when it is cold and it wanders between in gear and not but once it warms up it is good to go.
I have the same issue, did you fix it?
@@DRDWISCONSIN yes. I had the tranny serviced and with a new filter it’s awesome
2005 4x4 6.6 five speed had speed sensor codes and shifting issues replaced all speed sensors and scanner shows good operation. still coding speed sensor p700. Sometimes it starts out in fourth gear, sometimes stuck in 1st. also abs brake actuation. Checked both TCM connectors and found no pulled out terminals. put it back together and have a no crank. batteries are good shift indicator shows no position (not in park?).what could have happened ? now I cant even test drive to see if connections just needed cleaned ! any help out there would be awesome
Popped pcm fuse so you guys know. still coding output speed sensor. will update later
Update?
Lol! It’s been awhile so I’m going to be brief. Found broken wire(s) in harness from TCM to power block. Then found broken wire to sensor in harness from power block to sensor ! Repair wires and transmission worked perfectly for about 6 months until limp mode started happening intermittently. Then found pass through plug contaminated with transmission fluid causing shift solenoid codes. Replacing plug fixed this and customer has been having no issues with transmission since then! Thanks for bringing this back as I did find several issues there! Cheers!
Hey brotha, my transmission has 42 different codes, and it did the same with 2 different transmission swaps of good transmissions. im gonna replace the internal wiring harness. Would you do this next, or what is your advice? i was thinking bad TCM, though, with the random DTCs.
two different transmissions and 42 codes on each sounds like bad tcm. We usually dont see that many pulled pins at the tcm to set codes like that. I would investigate tcm.
Hey I have a 2002 model international and i have every gear but reverse and I replace valve body speed sensor shift sensor on side ot transmission. Could this be the tcm I replaced the valve because had a stuck valve in solenoid a. Any information would be helpful thank you. Levi
Also the range inhibit light comes on in reverse but not any other gear.
I have a 06 Chevy 2500 with the 6 speed Alison replaced the tcm do to really hard shifting didn’t fix it it’s a new tranny as well could this be the issue on a 6 speed as well?
It’s not bad TCM on 6 speed
@@SpartanAutoworx ever see a 6 speed shift hard like that or any ideas? Tranny was replaced with a new one a year ago tcm is new and reprogrammed I’m at a loss
so i have an o1 gmc sierra 2500 hd w 8.1L gas and allison 1000, also have an 02 Silverado 3500 dually w LB7 and allison 1000. the Silverado has be wrecked and is a parts truck, my 2500 is my daily, yes fuel cost is horrible looking to change soon as weather permits enough work to do so. 3 days ago and 3 other times while slowing down to make a turn i get the grinding sound as if shifting a manual with out a clutch just not as loud, its a steady grind while slowing for turn my light is green but at about 20mph grinding stops much the way it did other times intermittently, i know nownits not abs pump as i never pressed it. also this time service light, im accelerating slightly out of turn, its in way too high a gear but holds it, luckily my destination part store is next turn and around to park. whole time stayed in same high gear. dignostic tool says tcm failure, short to ground, 4th gear ratio too high, and something about a solenoid, also relists some of same codes twice or more, for a total of about 10 codes. used 4 low to load onto my trailr to pull home, offloaded same and parked. will check connections soon. whats chances tcm from 02 diesel 3500 will work on 01 2500 8.1 gas. sure sbift points will be different rmps and torque converter and pressures may be different. can it be flashed to work, how much $ if i pay shipping both ways. i dont trust the local dealerships, from exp they are parts changers only.
That allison 5 speed tcm will work. Send over both vins and we can check calibrations. If it needs programmed its $110 with return shipping.
I've got an 03 gmc with an 8.1 and allison 5 speed, I've been having an issue with starting, check engine light threw a bunch of trans codes, hard shifting, gear indicator has been working off and on, the main thing is the starting issue. Sometimes it's no crank or clicking of the relay at all, sometimes it clicks or starts to crank and then cuts out before the truck fires, I don't remember what trans codes it has threw me, but I've replaced the starter, connectors on the wiring at the starter, ignition switch all with no success. I'm going to try checking the tcm harness but is there anything else you guys would recommend?
Fuse box or wiring goign to the fuse box. I would guess wiring going to fuse box
@@SpartanAutoworx I have had the fuse box out twice to check all the wiring, I have power everywhere I need to have it in the fuse box, no corrosion, broken wires etc. And when I have no crank no start if I pull the starter relay out and jump it with a wire it turns right over.
Hi!! Where can I find the tcm on a 2014 ltz 5.3l 2wd chevy silverado 1500 ? I have a p700 code, all symptoms indicate it's faulty. I could not find it anywhere near battery or inside hood. Some say it's in the transmission itself but where I couldn't see it.
6 speed inside the transmission
Yours is gonna be inside the transmission
I have a couple electrical codes p0700 p0500 p0727 all sensors for electrical problems, solenoids p0748 and p0778 shifts just rough from P,R,N,D won’t come out of 1st gear
Shop put in a new OEM TCM programmed and re-flashed re wired the sensors and pigtails
Gave me the truck back at no cost to me and said sorry they couldn’t fix it.
I changed the valve body with all new solenoids , the internal wire harness I’ve changed all the sensors out still getting the same codes I’m at a loss
Will try this next
Hey there.. took the pin connector apart.. couldnt see much but after applying dielectric I had a small spark on clear pin group..for got to pull battery connections .. Now truck woult turn over.. no shift indicator but everything else works.. any ideas?
Check power. See gmflash.com/allison-5-speed-wiring
A specific fuse?.not sure where to look.
PCMB fuse.. thank you!.. also MIL code is gone for now.. will drive and see..
Hi I'm new at this. I have an 01 2500 HD 8100 engine with the Allison 5 speed. I get an intermittent overheat on my dash info monitor. Along with the gauge going up to 300 degrees. Checked the temp of the fluid. Also checked the cooler lines. Appx temp was 140 to 160 F degrees. Changed both filters, oil etc. Checked oil lines had no blockage. Still reads high temp. But does also drop down to normal in a second. Please help. Jim
Could be
TCM
Temp Sensor in the trans
Wiring
Have to check it all out.
Have the exact same problem. Replaced Manifold pressure sensor which has temp gauge inside and still have the same problem. Only happens when trans is at operating temp normally while at a stop. Really intermittent at one time it didn’t happen for over a year.
James, did you ever get this issue solved? I am having this issue on my 2001 Silverado 3500 8.1 after having the trans rebuilt about 4000 miles ago.
I have a 2001 Silverado 2500HD 8.1L with Allison 5 speed tranny. If I purchased a used TCM from another 2001 Chevy Silverado exactly the same as my truck, do I have to reprogram the new TCM before installing it?
Do they sell the wiring harness that goes into the TCM? The clear control module was loose and the plastic piece that sits on top locking the pins in place was also loose. I did my best securing it and prevent the connecting harness from rattling. But I will see what happens and any information from you would be appreciated.'Thanks
I have a 2003 Fleetwood motorhome with a 8.1 engine and a 5 speed transmission Allison having problems with my downshift button the transmission works fine except the button stopped working doesn't downshift to 4th what could be the problem thank you
I would say wiring
Hi, my Duramax works fine when it is cold, however after driving for 1 hour or so, then stopping, parking, then starting up and driving again, the shift indicator does not show up under the PRND3.., but will jump to the 3 when shifted to drive and it will not drive, if you let it cool for about 20-30 minutes you can get it to go into drive and go, however after driving another 45 minutes to and hour it goes into a limp mode, shifts down, over-revving the motor and then has to be cooled down before being able to drive. Is this the TCM? I took the TCM off, removed the plugs, looked for corroded plugs etc then put some dielectric grease back on and reassembled, hoever it did not fix it. What do you recommend?
What year truck? Any codes?
Did you fix this problem mate?
Mine is doing the same
im having some issues with my 05. local trans shop says its showing code for solenoid b but they just replaced solenoid b and one or 2 other solenoids and still same problem. whats the best way to contact u guys and ask a couple questions and explain what the truck is doing?
Give us a call on monday
Hey man I got a 05 Lbz, with the Allison pretty sure it’s a 6 speed ? But recently it was slipping and I put stop slip in it it ran like a dream for 6 months engine recived it’s normal oil change the truck has 87,000 miles... and on its second transmisson although it was passed down to me I don’t know much about the first replacement but today it touched 200 on the gauge and started to go over just a tad and was stuck in 1st gear I pulled over turned it off and on and got back at it worked fine what would you recommend for me this shit is a pain in the ass
So it showed that it was overheating or high but when you cycled the key it went back to normal? Did you read for codes?
@@SpartanAutoworx it was at like 207 ish not really over beating but when it got hot it started slipping I put stop slip in it pretty sure I made a big mistake
2001 Chevy 3500, 8.1L gasser with the Allison 1000 5 speed.
I'm getting an erratic trans temp reading on my gauge cluster. Sometimes its pegged at cold startup, sometimes it shoots from zero to 200, then creeps up and stays. Then it might drop to zero or regular operating temp, all over the place but not a twitchy gauge like these clusters sometimes exhibit. When it pegs hot, I get a "trans hot, idle engine" message and trans shifts hard, but only shifts this way while gauge is reading incorrectly.
I've checked these pins you talk about and seated them all. I can't see any issues with them, no retention tabs are broke. I was able to unseat and re-seat every pin on both connectors even though none appeared loose to begin with. I checked trans harness for fluid in plug at trans, there was none. Ive checked resistance on on the pins for the temp sensor in trans and according to the specs for temperature/resistance nothing seems out of spec. Ive checked all grounds I could find, and I looked them up to make sure I didn't miss any. Including the ones on the interior near the gauge cluster under the a pillar
At this point the only things I think it could be is TCM. Only caveat is it appears the previous owner/owners spliced in a shitty old security system but it did not appear to be hooked up anymore as most of the wires where just cut and Ive had no typical failing aftermarket security system issues like no starts or sudden dying etc. so Im not sure if thats contributing to the issue or if its just a distraction that needs attention later.
Do you think it sounds like my TCM has failed or do you think I should keep digging at the botched wiring job under the dash for maybe a bad splice or tie in?
Thanks for any help. I tried to exhaust all options I could before I asked you.
HAVE YOU EVER FIGURED OUT THE PROBLEM?
@@BIGWHITESNEAKERS yes. It was the tcm module. Replaced and its been fine ever since
@@Backwoodsmachinist Where did you source a TCM replacement from? New or used?
I got a question if you have the time. I push my tow button and no lights come on. I do have a edge evolution tunes on my truck. Do you think that's a button issue or a wire issue?
tow haul button? check for broken wire in orange sleeve on the column
can you flash a 5 speed TMC to control a 6 speed Allison ?
Negative I can not
Could this cause multiple issues, i just bought an '01 with allison 5 speed after he fixed p0722 & p0748. Solenoid replaced but speed sensor was the real problem. I purchase and get back home about 2 hours away to it putting out p1721 so now an issue with the solenoid next to the last? Older video but hope to get a quick response wont hurt to try instead of waiting i guess.
Oh and most times indicator lights blink of R and D, if it does go into gear i only got reverse and 1st, no other codes
Fast update: def not apart of my problem
Hi I have a question for you. I have a 2005 chevy silverado 6.6l diesel. i seem to have transmission problems but no codes?
What is it doing? Need more info if you have no codes.
right now it drives great in all gears and even goes into reverse. once the transmission heats up to normal operating temp but not overheating. then you go and put it in reverse and it doesn't work. acts like its in neutral and show the range shift inhibited message??????? I changed nsbu switch, pressure switch, pc solenoid. and still same thing. Should i try a new tcm? Also i went out today and unplugged the harness from the back of the transmission. the round one, along with the connector to the nsbu switch to check wires. do i have to get a transmission relearn if you unplug these harness. I have the 2005 Allison 5 speed trans. please any help would be appreciated!!!
I'm having an issue where my truck losses reverse and when I shift into drive it slams into gear and acts like it's in 2nd or 3rd gear..service light flashing..shut it off for a bit..then it stops and I have reverse and shifts normal into drive..truck isn't drivable like this but when the service light isn't on the trans shifts great zero slip..I'm going to do what you shown hopefully it helps..was a plow truck
Sounds like wiring
@@SpartanAutoworxthanks for the reply..I figured out how to use my scanner..narrowed it down to a bad turbine speed sensor in the trans
Hi I have a 2001 2500 duramax and it will not move when I put it in to gear. When I go back to put into park it grinds like It would if I was rolling and just through it in park. Any suggestions on what to check i have tried it in 4 lo 4 high and two while drive I really don't want to jerk the tray and transfercas out and replace if I don't half to. Any help would be great thank you
If its grinding sounds like something is bad inside the trans.
2007 Chevy 2500hd 6.0 Allison trans drives almost perfect in"D" , but when I select tow/haul mode rpms jump WAY high like over 4000rpm when I'm trying to slow down, could these connectors be the problem as well?
esco361 that would be your engine breaks I believe
Yeah thats the engine brake its supposed to do that. It down shifts to slow the truck and trailer down without wasting the brakes
I have an 03, 41 transmission codes pop up and my engine won't start now, I'll double check all my pins but would a bad TCM cause a no start issue? I've checked everything, the only codes I get are transmission codes.
Thanks
Gas? Diesel? half ton?
@@SpartanAutoworx diesel, 6.6 Duramax
The truck does fine 1st 2ed and 3ed gear but want go into 4th or 5th and when it gets up to temp it try’s to slip out of gear. But it does fine for in them gears until it gets warm. What do you think could be wrong?
Only does it when the temp goes up?
And I took the trans pan off and that little hole up in there where you can see the clutch’s you can move the clutch’s around a quarter of an inch so I think my clutch’s is wore out in it
I am having a check trans and range inhibited lights on an 03 international 4300 truck and it's stuck in low gear and won't shift into overdrive..notice the speedometer gauge isn't moving up.
What codes?
Check for power at the connector and report back.
Well I took ur advice and now my truck wont start. Was supposed 2 disconnect my battery first ?
I never disconnect the battery. That’s just me though. Does the park reverse neutral drive register on the cluster?
I have a 2002 6.6 turbo diesel and every time you try to get on it she will not pass 2,500 rpm and won’t shift and hold the gear and turbo unless you take your foot off the gas and give it gas again I don’t know if the issue is the passing gear or just something wrong with the transmission in general please help!
Hey I have a 2008 Chevy Silverado 2500 hd with a 1000 Allison transmission and I have a code “p0762 shift solenoid c stuck on “ do you know how to fix it?
Sounds like bad solenoid
Good afternoon
Thanks for sharing the video
Where can I buy those connectors of a gmc c5500 transmission allison 1000
I'm having trouble with them
Any luck with yours? Am also having problems with my 4500
I have an 2005 Duramax and I was giving me a code when we put the scanner on it P0700 Transmission Control failure and P2810 pressure control solenoid G (electrical). It wouldn’t shift out if first so we changed the pressure solenoid and now it will up shift to 2nd but won’t shift out of 2nd. Also after it shift to 2nd when you put it in park or reverse it jerks real hard. I’ve been fighting this for weeks could you help me?
You have checked the conectors?
No not yet that was going to be my next step in the morning
Is there a place to get the wiring harness to the TCM? I had a recurring PS leak and fluid deteriorated the wiring loom and I'm afraid of some wiring issues as a result. I thought maybe a new harness would help. My truck 2003 GMC Sierra 2500HD Dmax is going into limp mode because of a high transmission temp signal. I know it is electrical because it happens randomly and sometimes when I initially start the truck. I measured the temp of he trans pan with a laser thermometer and it is within op temp. For a while I could jiggle the wires going to the TCM and it would go back to normal until it happened again. I took the jacks apart and made sure the pins were properly seated and plugged it back in and I still have the same problem. I didn't have this problem at all until I changed the PS pump and had to move the TCM out of the way to take the shroud off, I'm sure it hadn't been moved since 2003... any advice would be amazing! Thanks
Jacob,
Remove the connector and make sure the sockets are in place and there's no green corrosion. Reassemble. Use a tie wrap and gently pull the harness at the TCM off to the side a little. I used my pocket knife to do the same and the problem disappeared. You have a floating short that will come and go. Go slow and methodically move one thing at a time. Not too many changes at once or you'll never narrow it down.
That or just carefully replace all the sockets and see if that does it.
Thanks Robert! I just saw this! I'll try it! You mean just give the sockets at the TCM just a little pressure to the side?
@@Jacobtaylor1775
Correct, it doesn't take much. If your problem disappear s replace the female sockets for any codes that are present.
I have a p0778 please help check everything can’t figure out 😢
Email with details
Hey man I have a 2001 2500hd with the 8.1l v8 and it keeps on shutting off on me out of nowhere and I’ve replaced a lot on it and it still shuts off what do you think it could be
Codes?
Hi this is Bob . So I just watched your video on the five speed Allison pinouts. Let me go back a little. A customer of mine was on the highway this morning at Cruise speed and all of a sudden transmission has no gears while driving. Vehicle was towed here and has no engine light no pending codes and the transmission fluid was in pretty good shape only about a quart low but it is whining in every possible gear and does not move when I put it in drive I can hear the drum or the torque converter spinning for about 20 seconds then the whining stops and drives indicator flashes. Could this have anything to do with those pinouts to the transmission control module ?
No tcm codes at all? If the PRNDL is flashing it should code out. I would check pins clear all codes and retest. I have seen allison trans code out and drop all gears. Clear codes and back to working. Usually only see this with low battery volt at start up
My truck did the exact same thing. Did you ever pinpoint the issue?
@@chadw9046 No. Sold the truck to someone who had a transmission and transfer case wrapped up nice and their garage that just needed a decent truck to put it in lol. Yes I cheated and took the quick and easy route and sold it.
What is the part number for this? I'm having a very hard time finding this harness. 04 duramax LLY reading code p0872, new valve body, nsbu, throttle cable. Really interested to find this harness
Sorry this is over a year ago but did you ever find the harness name I'm looking for one
i HAVE A 2009 duramax (170K miles) and it throw code p0700 and p0708 and it said stabil trak service required. I had to limp it home and every once in a while i heard a clanking sound... So after researching some forums I replaced the NSBU and ignition switch. The stabil trak warning went away but the 708 code has not. it still says transmission range sensor circuit high input. Transmission fluid has been changed religiously and looks good. Could this be my problem? Should i replace the harness before the TCM? Thanks.
How did you fix your p0700 code? I’m having trouble
Same exact problems here on my 09 any advice or how did you fix yours?
My 03 f650 did a unusual hard shift and check trans light came on. Truck went into a limp mode and stayed in one gear. Parked the truck for an hour or so started it up check trans light was off and shifts were normal. After about 30 minutes light came back on and went back to limp mode, could this maybe be my issue?
I doubt it. Totally different system on a ford
Where are you located?. I have the po700 transmission shift hard sometime . I also have u100
What are we working on?
Wondering if anyone of you had the ECM B fuse blowing first with the original TCM? I did. Then I bought a second hand TCM and no more fuse blowing. But I've got no communication with the transmission at all. Code U2106 Keeps coming up with my cheapo scan tool. And even with my snap on Solus ultra still no communication with the transmission
Bad replacement?
Thanks for the video. I have an 03 gmc with the 5 speed allison. I have codes p0846 and p0700. It seems to start in third and stay in third. Reverse is fine. Up to this point I haven't had any problems with the transmission.
Check the pins and maybe replace the NSS
@randy did this help? My truck is throwing the p0846 code. If so what is the NSS?
I have a 2016. duramax with allison. cooler weather now. not cold though. 40*-42. Fahrenheit. backed out of driveway and put in forward moved 10 ft and it stopped pulling and D started flashing. switched through gears and R flashes and still wont go. shut engine off 4 or 5 mind starts and goes. what could be?
Bad TCM
@@SpartanAutoworx dang that sucks. heard could be nsbu?
having issueson 07 LBZ..... changed water pump and boom now the truck is acting all crazy.... not shifting properly . is it possible the TCM is damaged? its a 6 speed ..... is there some fix like the 5 speed i should be looking for?
Any codes?
@@SpartanAutoworx nope no codes
2001 gmc sierra, has been throwing p0700 for two years, pulled tcm connectors, dielectric greased, no change, dropped tranny pan spun new filter on changed fluid no change. what to check next? all winter long it wont throw code once, weather gets warmer and it throws code second, third day than two weeks later(randomly throws it) when it throws it, it is only in park and the shift indicator light goes off, shut truck off, turn key on shift to drive shift back to park and restart and it is fine again code goes off until it randomly comes back on. thanks
Pins or maybe NSS