Geez I'd pay to see you and Richard from precision transmissions get together...both of you are so good to watch at your trade...love it...greetings from Australia.
Just rebuilt one of these in the parking lot of the rv park. Fairly decent. Nothing like most other transmissions ive messed with. Just so easy to put this together.
Thanks for the video! Awesome detailed explanation of how the internal components work together. Appreciate the tips on options where special tools are needed to get the specific task done. Rebuilding my 6L80 in a 2014 Silverado, failed torque converter at 120k miles. Preferred to have my reputable local shop do the repair but their backlog was ~6 weeks to get it in. Videos like yours and an ATSG manual allowed me to tackle the project myself.
This videos got me very interested in transmissions, i find it fascinating how they work after seeing this. My gearbox is just about shot and am tempted to try and do it myself, how did you go with it?
Dude I’m 16 and I just don’t have the money to pay a shop. If I don’t rebuild it myself, I won’t have a vehicle for high school. 😢 I think I’m gonna beg the guys at my local transmission shop to teach me because who doesn’t want to teach a high school kid their expertise. Most kids don’t just say oh I wanna learn how to rebuild a tranny. But now I have to. I want to fix it myself but my parents want to sell my 15 sierra 223k miles all original.
The transmission is literally the most complex mechanical piece on a vehicle. It’s all downhill from there. And there is a alarming amount of people who don’t understand how the trans works that they are rebuilding. 6 speeds and up have a lot of moving parts and how they work together to create each gear.. which clutch packs apply in a given year… most guys that overhaul them don’t have a intimate understanding how how they work. They just know how to inspect and replace the parts. A true technician is worth is weight in gold
This is the best educational video that I have seen so far. He breaks each section down and I like the fact, that he doesn't pop out all the spacers out when he pulls out each device.
Thank you for the videos. I've downloaded this one and your video on the electrical and hydraulics for this transmission, and it is because of videos like yours that somebody like me is able to repair my own transmission, engines, and pretty much do all the things that other people pay thousands of dollars to have done for them.
Any guy that does not use a battery-operated drill to remove and replace bolts is the guy I want working on my stuff. Getting it done right is more important than getting it done quickly.
Well, by looking at all the clean parts, it's a safe bet this trans has already been taken down. That's not saying he doesn't also use hand tools only, but just saying this trans has already been worked on due to all the parts being clean and dry. Great video!
Just getting on the bench and learning the 6L80 built two so far no problems going back over your videos because this last one go forward in reverse lol taking it back apart Monday seeing what I can find. Thank you for making these very informational.
This was a useful video for me. Thank you for taking the time and sharing your knowledge. I am a master tech and have been working in professional shops for over 30’ years now. I have been able to tear down, diagnose (more or lees at times) and successfully reassemble/return to service several different units including now one of these. I still long to understand how it all works and what is actually going on during the different gear ranging. I would enjoy learning if I could find a class to attend and would gladly pay to attend a quality class. Thanks again! The explanation of the power flow was inspiring!
I’ve been slowly building the curriculum for transmissions at www.automotivetextbook.com/automatic-transmission-curriculum/ If you click on the chart, each box links you to a video, worksheet, or reference.
The automotive school I graduated from in 1973. It is one of the best, if not the best, automotive school in the country. Most manufacturers hire graduates from this school because it is that good. (yes I am biased!)
I think its great to stumble across someone who still works with natural pride and applies proper procedure when performing a skill. It restores my faith that some future techs are getting the right knowledge and also the correct way of applying the skills they are in the process of mastering. I will definitely let some of my younger gear head associates to invest their spare time into tuning you in.
Thank you for for these detailed walk through. Extremely helpful. Just did a low reverse sprag replacement, new clutches & steels, sonnax zip kit, sonnax line pressure booster, sonnax billet 1234 piston, and sonnax 456 apply piston on my turbo 5.3 12' sierra.
Keep up the good work, guys like you make RUclips amazing. The in-depth video and knowledge is amazing. You sir are helping to make people’s lives easier.
Greetings from the University of California! Amazing videos and information you have here! The planning and time involved are very evident to say the least...definitely a top notch presentation. I do a bit of automotive transmission work as a hobby and side gig so this info has been very helpful!
Just finished repairing a "come back". Still having problems. When driving and take foot off the gas, it feels like the brakes are applying when coasting, like its downshifting but slows down l
Thank you much for sharing this! I have never been in an ATX, only have messed with MTX units. I have a 2014 Silverado with the 6L80, it runs fine with no issues... I do have about 350k km on the clock though! I just like to have contingency plans and preempative learning, as nothing lasts forever and looking at 350k km... I would rather just rebuild before failure. The good thing is with the long time span this unit was used, spares are likely going to be avail for some time... But it is good to get an overview of some things that may be more prone to wear and failure. Looks like a bell housing and pump cover would be a good thing to have as original spares. I don't have a machine shop, but the price of them new isn't really too bad. My goal eventually is to have a donor truck, so I can rebuild and upgrade the engine and ATX from it ahead of time, without having my truck sitting inop in my shop. Then when my truck actually starts exhibiting issues, I can swap the rebuilt units in, and then be able to rebuild the worn and have as a backup spare. It certainly looks like rebuilding the 6L80 in one's garage is doable, with some investments or fab of tools. Thanks again!
That’s some good mileage from that trans. The torque converter failures are what tears the pump and bell housing up. If you rebuild a trans, make sure you upgrade the torque converter. Find a converter rebuilder that uses the Sonnax upgrades.
@@siuautomotive It certainly will be interesting to see how the trans looks inside, I really am surprised, with all I have researched. I never knew there were rebuild items for TCs, though that certainly is out of my scope considering the machining required on the cover. I'll probably have to find specific shops for rebuilds with Sonnax, as most I have found have not stated exactly what they use. I also have looked into Circle D TCs. It has been quite interesting looking up TCs and etc, thanks for the tip! I originally wanted to delete the AFM and cam a 5.3L... Which lead me to think I should also build up the trans and related items to better withstand increased power (or forced induction, which is my eventual goal). Can't thank folks like you, sharing videos. Look forward to seeing more videos from you.
What would happen if you add an extra steel/friction in the 3-5-R assembly? Was having a hard time obtaining proper clutch travel even with a thick snap ring?
I just had a new 6L80 put in my 4x4 2010 suburban I'm wondering when they changed the gear ratio the new transmission is lower geared then the old one but I like it better.the old one at 75 ran 1600 rpm and down shifted alot the new one at 75 runs 1900 rpm and holds 6th better doesnt shift as much .
Pvc pipe, cut in half long ways. Then, assemble both halves around the ring and squeeze. Rotate the halves in different positions while squeezing. Then, finish sizing with whatever components the rings seal.
sorry I was in a hit-and-run accident 3yrs ago I'm having and hard time through it. and it's no fun. sorry . Jay the Florida pool pump motor bearing repair guy When Service Calls Longwood approved ! that was good info 👨🔧 siu thanks
I have an 09 suburban with 6l80. 230,000 miles on it. I dont know if it's been rebuit or not. I have what i would describe as "shuttering" around 40-45-47mph at a normal acceleration what i would call 3rd into 4th gear (i could be wrong) with less, but some "shuttering " 4th into 5th. Some small rpm jumping duirng this, less thab 500 rpm. I notice that shuttering is lessened, or i just dont notice it as much when im at merging acceleration. I sitll owe 2k on this pile and have put years or work into it some im committed to fixing it. Im going to buy a screw press, compressor, slowly get ready, but what type of kits should i be buying? Im saving a lot of money doing it myself, so what's a nice mid range rebuild for this trans.
I replaced the selenoid shift control module on my 2018 1500 chevy and now it won't show the gear selector on the dash or move fordward but will reverse. HELP PRETTY PLS
During vacuum testing the valves in the valve body, how low is too low and requires the valve body to be replaced if the valves are new from Transgo? I noticed you had the 6-2 select test at 15 inches and seemed concerned but then didn’t say if it is acceptable or not. Thanks!!
Sir, can I install Sonnax high-performance pump slide spring 104534-HD for 100% STOCK GM 6L80? 2011 camaro SS. The Sonnax spring is stiffer than OE and is able to hold the pump slide in a maximum-volume position, despite increased pressure and high engine speed in performance applications.
Do you have an upgrade converter you recommend for a Silverado 5.3 6L80? Thank you for this detailed video. It’s really nice to understand the drivetrain. Just subscribed.
Hi, if it's not much to ask, I need help finding a part. I have a 2005 Ford Explorer 4x4 4.6l Limited. Well, I just resintly replaced the transfer case and when I went to put the new one on I noticed some oil dripping. It turns out that the seal on the transmission side needs replacing. Dealer don't make it anymore. Can't find an original part. What do your recommend? I believe it's called "transmission output shaft seal". Some help would be nice from anyone. Thanks
I rebuilt a 6l80 using this video. I still have a slip under hard load in second gear. The only thing I didn't replace was the stator gasket. Could a leak somewhere on that only affect 2nd? Pressure is only reaching about 450kpa in 2nd, but 650kpa in others.
Well It was really only slipping in second the first time to, but when I pulled it apart it was the 1234 clutch plates that were completely wore out. I changed everything in the whole tranny including doing the two transgo kits. The only thing I didn't replace was that gasket under the stator. The pump looked good, there was no wear anywhere. Torque converter was fine but I replaced it anyways. I didn't have much ability to air test anything.
The 1234 pistons have a problem with cracking. You might pull the valve body down and air check the clutches. The bridge seals sometimes leak. If it air tests well, it might be the tehcm, but I wouldn’t think that’s it since you said it’s dropping pressure.
Awesome video! Im converting my awd 6l80e to rwd, seems pretty straightforward just buy a rwd output shaft assembly and new tail housing and put it all back together ??
Hi. Great learning video by the way. Which overhaul kit is a good one to go with. I'm looking at the atp master kit or a transtec kit with bonded pistons. Which kit has more to offer. My wifes 2015 sierra torque converter crapped the bed and now its time for a rebuild as $8000 in the shop canadian is just unrealistic for a transmission overhaul. Ill be also getting the sonnax zip kit a new stator and pump, and a new torque converter. Any help would be much appreciated. Ive rebuilt the 4l60e's. So now the 6l80 for the rebuild.
Hello I have a question 2014 6L90 transmission does good until it heats up then it doesn’t want to pull in reverse, I have it torn apart but I don’t see anything worn. Can I please get your opinion? Thanks Herman Joned
Hello Sean. I am hoping that you can point me in the right direction. Do you have a source for GM part numbers on the 6L80/6L90 transmissions? I have one apart & I seem to have misplaced the thrust washer that goes between the front input planetary & the 4-5-6 clutch housing assembly. The ATSG book shows a 4 tab washer. I assume that it's a 3 or 6 tab washer as the front planetary (6L90) has 6 holes. Thank you, sir, for sharing your wealth of knowledge.
I believe it's 24232426. You can google it and see some images. It's labeled as a sun gear thrust washer, but I believe it's for the planet. I used repairlinkshop.com to search OE parts. Set up an account (it's free) and you can view the factory catalogs. That thrust washer is only like 4 -6 dollars.
I appreciate you sharing knowledge for everyone to see. I have a 2008 Sierra and I have just pulled the engine to change out the cam bearings because it has low oil pressure. This is my first time pulling an engine and before this have only done basic repairs. With my limited knowledge I made a mistake when attempting to pull the engine out. I didn't loosen the torque converter bolts and when I was attempting to pull the engine out a quart or two of transmission fluid came out from the engine side of the bell housing. I was wondering if I screwed up the torque converter or if I will have to tear apart the transmission as well and do some repair to possibly the pump. After watching your video I am considering doing the transgo kit for the pump since the truck has 160k
Inspect the converter hub to see if there’s any damage. I would definitely install the transgo shift kit since it’s out, and I’d actually replace the converter while you’re in there. The converter is a weak link on that transmission. A reman converter from a good supplier like Precision of New Hampton, Dynamic, or Florida Torque Converter will have many upgrades that even a stock engine should use.
Thank you, You do very good job & great video. & What is the the best upgrade torque converter for 6L80 transmission? is it TCI torque converter, B&M Racing torque converter or RECON TOW PERFORMANCE TORQUE CONVERTER FOR GM 6L80/90 ???
Personally, I would call Precision of New Hampton to get a performance converter. If they don't have one ready, I call Florida Torque Converter or Dynamic Torque Converter. They all should offer a converter with a billet cover and a billet piston. I'd opt for OE lining and then do a HP tune to it.
Thank you! I'm dealing with a 6l80 intermittent shuttering and fluid is jet black, dropped pan replaced filter and fluid, helped slightly but, my transmission guy says torque converter is the issue, he wants small fortune and is booked out weeks, I own an appliance repair business and it's my only truck 😳 I thought about purchasing a torque converter and replacing that myself, just not sure if pump is toasted..
Hi there great video and very informative. My question is is there any way or any kit out there that changes the first gear ratio. Any information much appreciated. Thanks
Sorry, I’ve never seen an alternative gear set with different ratios. TCS makes a billet rear carrier, but I think they use the stock plant gears, because they require a core charge when you buy their carrier.
hello sir good video once again. I am having issues and I wondering if you can give some input, i tested the low revers with compressed air as you did but I only got movement on the very right port. the second from the left did not make it move at all. The transmission is on the truck, just dropped the pan and tested it. there is still some fluid in the transmission. thank you for your help.
Hello,,,i juste built a 6l80,,,. i can not turn the shaft ( in bell housing ) by hand...but with some pliers its easy and smooth...is it normal,,,thank you
hi its all good !!!...it was the new pump bushing that was a little tight... polish it with 2000 grid and now its A1...had to do the same thing in the past for a 4L80
I live in Carbondale and have been having problems with my 18 Sierra K1500 with the 6L80. Would you happen to know any good shops that do a proper overhaul locally? I dropped the pan and noticed the fluid was black, smelled foul, and the magnet was covered in metallic paste. Took it to a shop figuring it was the torque converter, they agreed but said the transmission didn’t seem to have any other problems. However, this wasn’t a transmission shop so I’m not sure how thorough they got. The problems I was having before the torque converter was replaced, they used an OE TC, are now pretty much all back. Kind of at a loss. Any suggestions would be much appreciated.
What happens if you have no free play in the 1-2-3-4 and 3-5-R clutch packs? i've disassembled and reassembled them several times and cant get the prescribed clearance. I thought there might be a problem with the pistons, but have redone them several times. Changing the snap ring thickness to the min wont make a difference. I bought the 6L90 trans out of a 2010 diesel ambulance with no fwd or rev movement. Fluid was not burned. I didn't check the filter for cracks which would be the most common cause. There was no metal in the pan and no obvious problems found with disassembly. Thanks Bob
Was there clearance before taking them apart? If so you must be assembling them wrong somehow. Is it a new drum? The 80s are different than the 90s. There’s a different apply ring as well. Maybe a parts mis- match. Regarding the no movement, I’d make sure the torque converter is good, make sure to check the check balls to make sure they haven’t shrunk and are in the right place, make sure there are no cracked films in the tehcm, Some have had the rear output gear shear. If you have a pressure gauge, you could verify pump pressure. I believe a sticking compensator valve can cause no movement. A gauge and checking for dtcs would likely help.
I found a snap ring improperly installed on the 3-5-R piston. Another U-tube video said that the 6L80/90 trans used a different number of steels and friction plates. Removing 1 set from the 1-2-3-4 set did the trick. The manual I bought said it was for the 6L80 instead of the "90". pictoral in the manual indicated I had too many 3-5-R steel/friction plates installed. I find it odd if the 90 is longer than the 80 why would the weaker trans have fewer plates? my freeplay is within specs now. Thanks for a very informative video. Bob
I need a press like that. I can easily make one but I need that accessory your using. I've seen one before. What is it called, maybe even a part number?
If you machine the bell housing what about the pump housing thickess and the vanes. You are gonna need to do something to get that .001 to .002 back. You didn't say how to fix that part?
Yes, whatever thickness removed from the pump pocket will need to be removed from the pump mounting surface. There needs to be about a .0015 gap between the rotor and slide and the pump mounting surface. Some will also machine the surface where the bell bolts to the case to keep endplay the same, but some will use the superior or sonnax shims to adjust instead.
Hola tengo un silverado 1500 2015,vivo en hollywood florida ,podria recomendarme al profesional de confianza y responsable para reconstruir mi transmision .
Very informative. Question..what year did they change from rotational rings to non rotational rings on the pump. My buddy has a 16 truck and smoked his 6L80 good. Hardly moves. Dealer told him ya ots the converter. I droped the pan and the fluid was thin, VERY dark and smeeled extremely burnt. Magnet had so much metal and even more in the pan wasn't even on the magnet. Well I've got a 11 6L80...can I just swap the "guts"
You should be able to switch the guys. The non rotational stators were very early, like maybe 08 and earlier. So it shouldn’t be a problem. I suggest installing the transgo kits in it while it’s apart.
It depends. The Silverado might have a 6L90, which is a bit longer than the 6L80. Plus the 14 model will have a different TEHCM, that’s an updated part number, but the plugs are the same. I don’t think you can factory reprogram one to think it’s the other.
First off thanks for an amazing educational video of the step by step. Question what rebuild kit are you using bc I have the same transmission 6L80E MYC. And I’m trying to find one that includes everything I need
I believe there's a different piston drum, which has more surface areas on the edge of it, which allows the more pressure or easier pressure to be applied to the clutches, which is a upgrade aftermarket ,so are there other aspects of the internals which can make it stronger and last longer?
What would cause the center support to not slide all the way into the snap ring groove? I have spun the output shaft and the sprag does come down but still it won’t clear, the center support does clear with the gearset and sprag removed, if I take the Torrington bearing out it also clears, it seems like I may have a problem in the gearset? It’s a 4wd gear set and I did take it out of the output to inspect and it does go down into place but maybe not far enough? I’m at a loss and thank you in advance!
@@siuautomotive thank you for the reply, it seems I have the bearings all in the correct orientation (outer race down) and the bearing between the gearset and the center support pretty much goes one way, there’s and edge that sits down on the sun gear
Great video What would cause first gear to go out completely one day and have it again the next? Did have a weird 1-2 shift under light throttle for a couple months prior. No codes btw
I could use some help. I rebuilt my 6l90 after i believe the torque converter failed. everything went good. all air checks and clearances. had to replace the pump/bell housing. rebuilt the techm pressure switches and cleaned all the metal out of everything also put in the upgraded frictions and steels, Sonnax zip kit, put it all back and the pressure looks great. but now i have 3 fault codes (p0989, P0872, P0877) Low voltage on the transmission fluid pressure switches 3, 4, and 5. Reverse seems to be delayed, as well as shifting from 1st to 2nd and 2nd to 3rd. 3456 seem fine. Any help will be greatly appreciated.
Many times you'll need to replace the tehcm after a converter failure. That junk gets into everything. Did you use a tool to place the pressure switches? I know those pressure switches can be a pain at times, but they are essential to the operation of the trans. If any fluid pressure can get behind those switches, it'll throw codes and not work correctly. Lastly, did you replace the radiator or bypass the radiator with an external cooler? After converter failure, all that junk ended up in the radiator and likely plugged it. It's hard to get that out without a good flushing machine like a hot-flush.
@@siuautomotive I did use the tool for the switch rebuild. I air checked them the best I could. I used 3 cans of kooler kleen to flush the lines. Looked good in-between the 2nd can. I did clean the seperator plate with a wire wheel to get the bonded gaskets off. Kind wondering if that was a bad idea.
There is no switch two. I don't know why they skip 2, maybe it's something internal to the TCM, but switch one is for the 35R, switch 3 is for the 2-6, switch 4 is for the 1234, and switch five is for 456. If the codes are for low voltage, then the switches are stuck in their "normal" position, because when the switches ground, they allow current to pass to ground and the voltage is dropped in the TCM through an internal resistor. The switches kind of work opposite then you'd expect. They don't have pressure in the gear they are representing. So switch one won't have pressure (thus make contact and show low voltage) in Rev, 3rd, and 5th. I have an electronics presentation for this on RUclips as well.
Also those cans of cooler cleaner won’t get it all. Shops that use the hot flush will run it for an hour and still get stuff out of the cooler. The hot flush uses heated fluid and reverse pulses when it’s flushing to jar out the debris. If I had converter damage and I didn’t have a heated flusher that can reverse pulse, I’d either bypass the radiator cooler with a large air to oil cooler, but only if I lived in warm climates. If you have cold weather, it’s best to just replace the radiator.
Please help lol!! I rebuilt my 6l80 I did air check all gears holding except compensator feed should it hold air like the clutches and gears I understand how it works just not sure if it should hold air did the test no converter , tail housing or valve body
I don’t believe the compensator will air check as well as the clutches. When you rebuilt the trans, did you change that bearing in the 3-5-R/1234 drum? It has a seal built into it to seal off the compensator passage. If that’s installed incorrectly or the seal is damaged you’ll get a worse air check.
on my 3rd 6L80e they all worked great except this last one kicking my butt. Just as soon as I hit 4th gear I'm getting this whooooooooo noise with some weird grinding noise attached. it goes away as soon as I let off but comes back as soon as I reapply. I see nothing abnormally worn. all my clearances are within specs. Pistons are good. I suspected a bearing but they all feel decent! I'm struggling with this one. My planets look good! What do you think it is? It's only after 4th applies....Same noise before the build. same noise after the build. Hd converter. new pump assembly. new blue Pistons clutches and steels. changed rubbers and laminates in computer. no codes
@@siuautomotive it's working in 4th. after the build I drove it maybe 15 miles. I tore it back down and didn't see any excessive wear on the clutches. Ive searched this problem online and have found alot of guys experienceing and describing this same noise. Thanks for your time btw. thank you it's not slipping into 4th it falls into 4th and immediately noise let off the gas it goes away apply the gas noise with a weird grumble attached. I see nothing. I put it under the microscope all hard parts
@@siuautomotive I did find since it's a 2017 that I reused the number 8 check ball the undersized one. I put it back in it's original spot. the transgo instructions tell me not to use the undersized check ball. I'm going to change it to . 250 and see what happens
No sir. It's an old GM tool (kent-moore). They still sell them, but they are pretty expensive. There are other options, like this one from adapt-a-case: adaptacase.com/t-48909ac.html or this from ATEC trans tools: www.toolsource.com/holding-fixtures-and-support-c-1321_119_582/gmtransmission-holding-fixture-t0156b-wo-base-p-94383.html?tsqtid=809059
Hello sir! I got a 6l90 from a online parts place.they claim it got 45k miles. I pulled the TC out and got black color oil spilled. That got me wondering-did i get a really burned up unit? I never seen a transmission with black oil. Or its something new i don't know about? Thanks
@@siuautomotive it does smell burned. The fact is that i bought it as a low mileage (45k miles) working unit. But its been more then 30days. I will try and claim it as a loss with my credit card bank..
Any idea what would cause a 6L80 to “fall” out of 1st gear idle and “snap” into 1st gear once the rpms get to 1,500(doesn’t consistently happen). But only on shift pattern X and Y. But Tap shift commanded 1st or 2nd no issue
The low sprag slipping could cause this. I’m not sure, but the pcm might leave the l/r clutch on when tap shifting. The low sprag and l/r clutch holds the same component.
Hi hoping can help me, I'm using a GM LS2/LS3 Engine controller kit p/n:19354328 and want to run a 6L80E transmission, can you please advise what trans harness I would need to work with p/n:19354328?
Hello. Great video! It was such a great tool for reference. When doing an air test after a rebuild, all gears test good. However, the compensator doesn't hold pressure and leaks quite a bit. Is this normal? If not, can you recommend a starting place to look. Thank you!
I guess it depends if you have that tool for checking the 3/5/R drum. The compensator passage is found under that bearing on the drum. That needle bearing has a green seal built into it. If you didn't replace that bearing, it might be leaking from there. If you did replace the bearing, you might have installed it upside down if you didn't notice the seal.
@@siuautomotive I'm testing at the pump port with the transmission assembled and the valve body removed. I did not replace the bearing in the drum as it was not included in my trans star kit. I received a note in the kit stating there was shortage and they could not supply it at this time. Thank you! I'll take a closer look and let you know what I find
I was able to find a new 1234 35r drum bearing/seal today and replaced it. It is correctly installed. Testing it as I described after changing it still doesn't seam right. I do not hear any sort of engagement, just air moving through the transmission. It will hold pressure for a moment but leaks out rather quickly. Any other suggestions that come to mind? I don't know what other drums it travels to. Finding a solid diagram to understand the system has been difficult. Many thanks for the help!
I use kits from Witrans.com, transtar1.com or slauson.com. Also check the dealer, because sometimes their kits are cheaper. Download and signup with repairlinkshop.com to check dealer prices and availability.
@@siuautomotive great thank you! Very informative in your work! Thank you so much for the reply and the knowledge you give away! Keep up the great work brother!
In the 6L90 with 178k miles, what causes a 1 to 2 hard shift and a slow responding shift to reverse? Also got a pulsing feeling in 1st or 2nd. Parked it since and going nuts.. This happened after I let truck sit for a week when I usually drove it everyday. Any help is appreciated.
Are there any DTCs stored? Pressure switches are common failures and they cause all kinds of problems, but you usually get a DTC. The 3-5-R housing cracks and that could be your reverse issue. The pumps really wear out the pressure regulator bore and that causes high and unstable pressure, which could cause your harsh shift and could also cause the crack in the 3-5-R drum. Not to disappoint you, but that's pretty much the mileage people get out of this trans before it needs an overhaul.
@@siuautomotive no codes. I changed filter and fluid which was dark and had some fine flakes of metal. Forward gears felt fine after but reverse still lags sometimes. Looks like I'll be looking for a replacement
Just had mine overhauled at 160k it was always a hard down shift to first gear always shifting funky now it’s like butter I hope it stays that way I got 3600 in mine 🥹it hurt it still hurts I’m sitting on one cheek still
If it has more than 100k miles, I'd say it's worth your while to rebuild. They do have pressure switch issues, and simply fixing the pressure switch films might fix your codes, but that P2723 is related to the 1234 clutch and that piston is known for cracking.
What would be the cost of a new 6L80 made to be as strong as a 6L90, but with out the center driveshaft ,so can it be done, to make the 6L80 as strong as the 6L90, only because the 6L90E is longer and stronger, what can be done to make the 6L80E just as strong as the 6L90E but without turning it into a 6L90E longer unit?
The 6L90 has one more input clutch and one more holding clutch, plus the rear gearset is more stout. I don't know if it's possible to make the 6L80 as strong as the 90. TCS sells a upgraded rear planet, but aside from modifying pressures and maybe putting in performance clutches, I don't what else one could do. Thanks for watching the video!
Hello how you doing, I have an issue with a 2014 Chevy express 3500 ,6l90 trans. The issue is when your going 70mph you put the cruise control on then when it down shift from 6th to 5th, it won't release the 6th gear what so ever, the same shifting down and up manually, please help any idea what could be wrong. Any idea what could it be thks.
I'm not sure what you mean by "it won't release 6th gear." If 6th gear stayed applied, it would bind up and feel like someone hit the brakes. The transmission wouldn't last long if this were happening. If you mean that when it downshifts to 5th gear the engine flares up, then it might be an issue with the 3-5-R hydraulics. The 3-5-R clutch housing is known to crack. These transmissions also have issues with their TEHCM (control module and solenoids), so it might be something to do with that.
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I just finished my first attempt at a 6l80 rebuild and it was successful thanks to this video thank you very much
what brand torque converter did you buy and where did you get it?
@patrickwarden2933 we use either (precision torque converters) or (dynamic torque converters) from W.I.T
This was the most educational video I've ever seen
Geez I'd pay to see you and Richard from precision transmissions get together...both of you are so good to watch at your trade...love it...greetings from Australia.
Just rebuilt one of these in the parking lot of the rv park. Fairly decent. Nothing like most other transmissions ive messed with. Just so easy to put this together.
Lang tools has a nice set of snap ring pliers for the center support ❤️
If you have the three specialty tools I can see how it's easy it was a nightmare with no holder for the bottom or top and normal snap ring pliers lol
Most informative video of the 6l80 anywhere on the internet, very impressive, keep up the exceptional work sir!
Thanks for the video! Awesome detailed explanation of how the internal components work together. Appreciate the tips on options where special tools are needed to get the specific task done. Rebuilding my 6L80 in a 2014 Silverado, failed torque converter at 120k miles. Preferred to have my reputable local shop do the repair but their backlog was ~6 weeks to get it in. Videos like yours and an ATSG manual allowed me to tackle the project myself.
This videos got me very interested in transmissions, i find it fascinating how they work after seeing this.
My gearbox is just about shot and am tempted to try and do it myself, how did you go with it?
Dude I’m 16 and I just don’t have the money to pay a shop. If I don’t rebuild it myself, I won’t have a vehicle for high school. 😢 I think I’m gonna beg the guys at my local transmission shop to teach me because who doesn’t want to teach a high school kid their expertise. Most kids don’t just say oh I wanna learn how to rebuild a tranny. But now I have to. I want to fix it myself but my parents want to sell my 15 sierra 223k miles all original.
the amount of complexity to a vehicle is mind boggling
The transmission is literally the most complex mechanical piece on a vehicle. It’s all downhill from there. And there is a alarming amount of people who don’t understand how the trans works that they are rebuilding. 6 speeds and up have a lot of moving parts and how they work together to create each gear.. which clutch packs apply in a given year… most guys that overhaul them don’t have a intimate understanding how how they work. They just know how to inspect and replace the parts. A true technician is worth is weight in gold
This is the best educational video that I have seen so far. He breaks each section down and I like the fact, that he doesn't pop out all the spacers out when he pulls out each device.
Thank you for the videos. I've downloaded this one and your video on the electrical and hydraulics for this transmission, and it is because of videos like yours that somebody like me is able to repair my own transmission, engines, and pretty much do all the things that other people pay thousands of dollars to have done for them.
Idk how you don’t have more subscribers. I learned a lot from this vid!
Thanks for watching. Subscribers are growing slowly but surely. I guess we’re a little late to the game.
Any guy that does not use a battery-operated drill to remove and replace bolts is the guy I want working on my stuff. Getting it done right is more important than getting it done quickly.
Well, by looking at all the clean parts, it's a safe bet this trans has already been taken down.
That's not saying he doesn't also use hand tools only, but just saying this trans has already been worked on due to all the parts being clean and dry.
Great video!
Some of us can’t handle the wrenches and ratchets like we used to.
Exactly. Takes his time. I rushed through fixing my truck and forgot to plug in my fuel pressure sensor/regulator...lol
It’s expertise
All the parts are clean and dry and marked. Nothing in it requires power tools
Just getting on the bench and learning the 6L80 built two so far no problems going back over your videos because this last one go forward in reverse lol taking it back apart Monday seeing what I can find. Thank you for making these very informational.
So what happened? Did you miss the manual valve when installing the valve body? That’s pretty easy to do.
This was a useful video for me. Thank you for taking the time and sharing your knowledge. I am a master tech and have been working in professional shops for over 30’ years now. I have been able to tear down, diagnose (more or lees at times) and successfully reassemble/return to service several different units including now one of these. I still long to understand how it all works and what is actually going on during the different gear ranging. I would enjoy learning if I could find a class to attend and would gladly pay to attend a quality class. Thanks again! The explanation of the power flow was inspiring!
I’ve been slowly building the curriculum for transmissions at www.automotivetextbook.com/automatic-transmission-curriculum/
If you click on the chart, each box links you to a video, worksheet, or reference.
Great very informative and educational video. I had a pleasure to watch and listen to You. Thanks a lot.
The automotive school I graduated from in 1973. It is one of the best, if not the best, automotive school in the country. Most manufacturers hire graduates from this school because it is that good. (yes I am biased!)
I think its great to stumble across someone who still works with natural pride and applies proper procedure when performing a skill. It restores my faith that some future techs are getting the right knowledge and also the correct way of applying the skills they are in the process of mastering. I will definitely let some of my younger gear head associates to invest their spare time into tuning you in.
This a a fantastic video. I have spent a LOT of time watching transmissions be rebuilt. You do a great job presenting information and educating
Thanks for the compliment!
Thank you for for these detailed walk through. Extremely helpful. Just did a low reverse sprag replacement, new clutches & steels, sonnax zip kit, sonnax line pressure booster, sonnax billet 1234 piston, and sonnax 456 apply piston on my turbo 5.3 12' sierra.
Keep up the good work, guys like you make RUclips amazing. The in-depth video and knowledge is amazing. You sir are helping to make people’s lives easier.
Thank you. You're such a knowledgeable person. Excellently made video. I just did my 6l80 with a billet tq & output shaft its built
Greetings from the University of California! Amazing videos and information you have here! The planning and time involved are very evident to say the least...definitely a top notch presentation. I do a bit of automotive transmission work as a hobby and side gig so this info has been very helpful!
Thank you for this video, My 6L90 appreciates it!
Great video who is need repair gm transmission. All is clear 👍
Just finished repairing a "come back". Still having problems. When driving and take foot off the gas, it feels like the brakes are applying when coasting, like its downshifting but slows down l
Thank you much for sharing this! I have never been in an ATX, only have messed with MTX units. I have a 2014 Silverado with the 6L80, it runs fine with no issues... I do have about 350k km on the clock though! I just like to have contingency plans and preempative learning, as nothing lasts forever and looking at 350k km... I would rather just rebuild before failure. The good thing is with the long time span this unit was used, spares are likely going to be avail for some time... But it is good to get an overview of some things that may be more prone to wear and failure. Looks like a bell housing and pump cover would be a good thing to have as original spares. I don't have a machine shop, but the price of them new isn't really too bad. My goal eventually is to have a donor truck, so I can rebuild and upgrade the engine and ATX from it ahead of time, without having my truck sitting inop in my shop. Then when my truck actually starts exhibiting issues, I can swap the rebuilt units in, and then be able to rebuild the worn and have as a backup spare.
It certainly looks like rebuilding the 6L80 in one's garage is doable, with some investments or fab of tools. Thanks again!
That’s some good mileage from that trans. The torque converter failures are what tears the pump and bell housing up. If you rebuild a trans, make sure you upgrade the torque converter. Find a converter rebuilder that uses the Sonnax upgrades.
@@siuautomotive It certainly will be interesting to see how the trans looks inside, I really am surprised, with all I have researched. I never knew there were rebuild items for TCs, though that certainly is out of my scope considering the machining required on the cover. I'll probably have to find specific shops for rebuilds with Sonnax, as most I have found have not stated exactly what they use. I also have looked into Circle D TCs. It has been quite interesting looking up TCs and etc, thanks for the tip! I originally wanted to delete the AFM and cam a 5.3L... Which lead me to think I should also build up the trans and related items to better withstand increased power (or forced induction, which is my eventual goal). Can't thank folks like you, sharing videos. Look forward to seeing more videos from you.
What would happen if you add an extra steel/friction in the 3-5-R assembly? Was having a hard time obtaining proper clutch travel even with a thick snap ring?
I just had a new 6L80 put in my 4x4 2010 suburban I'm wondering when they changed the gear ratio the new transmission is lower geared then the old one but I like it better.the old one at 75 ran 1600 rpm and down shifted alot the new one at 75 runs 1900 rpm and holds 6th better doesnt shift as much .
Please explain how the oil pump works and how it is spoiled
Pvc pipe, cut in half long ways. Then, assemble both halves around the ring and squeeze. Rotate the halves in different positions while squeezing. Then, finish sizing with whatever components the rings seal.
sorry I was in a hit-and-run accident 3yrs ago I'm having and hard time through it. and it's no fun. sorry . Jay the Florida pool pump motor bearing repair guy When Service Calls Longwood approved ! that was good info 👨🔧 siu thanks
Very detailed video thank you very much for the time
I have an 09 suburban with 6l80. 230,000 miles on it. I dont know if it's been rebuit or not. I have what i would describe as "shuttering" around 40-45-47mph at a normal acceleration what i would call 3rd into 4th gear (i could be wrong) with less, but some "shuttering " 4th into 5th. Some small rpm jumping duirng this, less thab 500 rpm. I notice that shuttering is lessened, or i just dont notice it as much when im at merging acceleration. I sitll owe 2k on this pile and have put years or work into it some im committed to fixing it. Im going to buy a screw press, compressor, slowly get ready, but what type of kits should i be buying? Im saving a lot of money doing it myself, so what's a nice mid range rebuild for this trans.
I replaced the selenoid shift control module on my 2018 1500 chevy and now it won't show the gear selector on the dash or move fordward but will reverse. HELP PRETTY PLS
the bolts that hold the p/n switch and the 1 ne behind are 10mm the 2 on the side of the techm are 8mm
Good video, I may use this video one day if I have issues with mine!
During vacuum testing the valves in the valve body, how low is too low and requires the valve body to be replaced if the valves are new from Transgo? I noticed you had the 6-2 select test at 15 inches and seemed concerned but then didn’t say if it is acceptable or not. Thanks!!
Sir, can I install Sonnax high-performance pump slide spring 104534-HD for 100% STOCK GM 6L80? 2011 camaro SS. The Sonnax spring is stiffer than OE and is able to hold the pump slide in a maximum-volume position, despite increased pressure and high engine speed in performance applications.
I will be using this video to rebuild my 2014 Chevy Silverado 5.3
Do you have an upgrade converter you recommend for a Silverado 5.3 6L80? Thank you for this detailed video. It’s really nice to understand the drivetrain. Just subscribed.
Most good converter companies have upgraded converters available. Try Precision of New Hampton, Dynamic Converters, and Florida Torque Converter.
37min and 9 seconds you remove the silver washer is it normal to have wear on that part?
Hi, if it's not much to ask, I need help finding a part. I have a 2005 Ford Explorer 4x4 4.6l Limited. Well, I just resintly replaced the transfer case and when I went to put the new one on I noticed some oil dripping. It turns out that the seal on the transmission side needs replacing. Dealer don't make it anymore. Can't find an original part. What do your recommend? I believe it's called "transmission output shaft seal". Some help would be nice from anyone. Thanks
I rebuilt a 6l80 using this video. I still have a slip under hard load in second gear. The only thing I didn't replace was the stator gasket. Could a leak somewhere on that only affect 2nd? Pressure is only reaching about 450kpa in 2nd, but 650kpa in others.
I’d have to think the problem would be with the 2-6 clutch. Did you air check it. What was wrong with it originally?
Well It was really only slipping in second the first time to, but when I pulled it apart it was the 1234 clutch plates that were completely wore out. I changed everything in the whole tranny including doing the two transgo kits. The only thing I didn't replace was that gasket under the stator. The pump looked good, there was no wear anywhere. Torque converter was fine but I replaced it anyways. I didn't have much ability to air test anything.
The 1234 pistons have a problem with cracking. You might pull the valve body down and air check the clutches. The bridge seals sometimes leak. If it air tests well, it might be the tehcm, but I wouldn’t think that’s it since you said it’s dropping pressure.
Awesome video! Im converting my awd 6l80e to rwd, seems pretty straightforward just buy a rwd output shaft assembly and new tail housing and put it all back together ??
Hi. Great learning video by the way. Which overhaul kit is a good one to go with. I'm looking at the atp master kit or a transtec kit with bonded pistons. Which kit has more to offer. My wifes 2015 sierra torque converter crapped the bed and now its time for a rebuild as $8000 in the shop canadian is just unrealistic for a transmission overhaul. Ill be also getting the sonnax zip kit a new stator and pump, and a new torque converter. Any help would be much appreciated. Ive rebuilt the 4l60e's. So now the 6l80 for the rebuild.
Some of the jokes in here caught me off guard. Those small channel locks specifically made me look away from the screen for a bit. XD
Hello
I have a question 2014 6L90 transmission does good until it heats up then it doesn’t want to pull in reverse, I have it torn apart but I don’t see anything worn. Can I please get your opinion?
Thanks
Herman Joned
Revenioux gear set I think 4r70w
Is there 2 different output shaft assembly? And do they use different speed sensors?
Hello Sean. I am hoping that you can point me in the right direction. Do you have a source for GM part numbers on the 6L80/6L90 transmissions? I have one apart & I seem to have misplaced the thrust washer that goes between the front input planetary & the 4-5-6 clutch housing assembly. The ATSG book shows a 4 tab washer. I assume that it's a 3 or 6 tab washer as the front planetary (6L90) has 6 holes. Thank you, sir, for sharing your wealth of knowledge.
I believe it's 24232426. You can google it and see some images. It's labeled as a sun gear thrust washer, but I believe it's for the planet. I used repairlinkshop.com to search OE parts. Set up an account (it's free) and you can view the factory catalogs. That thrust washer is only like 4 -6 dollars.
Thank you sir, much appreciated
I appreciate you sharing knowledge for everyone to see. I have a 2008 Sierra and I have just pulled the engine to change out the cam bearings because it has low oil pressure. This is my first time pulling an engine and before this have only done basic repairs. With my limited knowledge I made a mistake when attempting to pull the engine out. I didn't loosen the torque converter bolts and when I was attempting to pull the engine out a quart or two of transmission fluid came out from the engine side of the bell housing. I was wondering if I screwed up the torque converter or if I will have to tear apart the transmission as well and do some repair to possibly the pump. After watching your video I am considering doing the transgo kit for the pump since the truck has 160k
Inspect the converter hub to see if there’s any damage. I would definitely install the transgo shift kit since it’s out, and I’d actually replace the converter while you’re in there. The converter is a weak link on that transmission. A reman converter from a good supplier like Precision of New Hampton, Dynamic, or Florida Torque Converter will have many upgrades that even a stock engine should use.
Do a rebuild video for a Dodge 545rfe transmission.
hi do you have rebuild info for a mitsubishi delica d5 2007 cvt auto trans cheers mate
Looking for the part numbers for the trans go kis you used on this video. thank you.
A overhaul can be done in less than 2 hrs that’s crazy
Thank you, You do very good job & great video.
&
What is the the best upgrade torque converter for 6L80 transmission?
is it TCI torque converter, B&M Racing torque converter or RECON TOW PERFORMANCE TORQUE CONVERTER FOR GM 6L80/90 ???
Personally, I would call Precision of New Hampton to get a performance converter. If they don't have one ready, I call Florida Torque Converter or Dynamic Torque Converter. They all should offer a converter with a billet cover and a billet piston. I'd opt for OE lining and then do a HP tune to it.
Great video, my best regarts to you and thank you for the time and information.
Thank you! I'm dealing with a 6l80 intermittent shuttering and fluid is jet black, dropped pan replaced filter and fluid, helped slightly but, my transmission guy says torque converter is the issue, he wants small fortune and is booked out weeks, I own an appliance repair business and it's my only truck 😳 I thought about purchasing a torque converter and replacing that myself, just not sure if pump is toasted..
I’d be willing to bet the pump is torn up by a bad converter. Sorry buddy!
I’d do a whole overhaul personally just to avoid having issues again
Hi there great video and very informative. My question is is there any way or any kit out there that changes the first gear ratio.
Any information much appreciated.
Thanks
Sorry, I’ve never seen an alternative gear set with different ratios. TCS makes a billet rear carrier, but I think they use the stock plant gears, because they require a core charge when you buy their carrier.
Very good video Sean
By the way great looking shirt
Thanks Gary!
hello sir good video once again. I am having issues and I wondering if you can give some input, i tested the low revers with compressed air as you did but I only got movement on the very right port. the second from the left did not make it move at all. The transmission is on the truck, just dropped the pan and tested it. there is still some fluid in the transmission. thank you for your help.
Hello,,,i juste built a 6l80,,,. i can not turn the shaft ( in bell housing ) by hand...but with some pliers its easy and smooth...is it normal,,,thank you
hi its all good !!!...it was the new pump bushing that was a little tight... polish it with 2000 grid and now its A1...had to do the same thing in the past for a 4L80
I have an 08 gmc yukon 6l80 . I have a p0677 line pressure sol b stuck on. Truck has no gears at all. What am I looking at
Valve body issue? But I’m not super. Versed
I live in Carbondale and have been having problems with my 18 Sierra K1500 with the 6L80. Would you happen to know any good shops that do a proper overhaul locally? I dropped the pan and noticed the fluid was black, smelled foul, and the magnet was covered in metallic paste. Took it to a shop figuring it was the torque converter, they agreed but said the transmission didn’t seem to have any other problems. However, this wasn’t a transmission shop so I’m not sure how thorough they got. The problems I was having before the torque converter was replaced, they used an OE TC, are now pretty much all back. Kind of at a loss. Any suggestions would be much appreciated.
Anyone got a link to those big mamajama pliers?
What happens if you have no free play in the 1-2-3-4 and 3-5-R clutch packs? i've disassembled and reassembled them several times and cant get the prescribed clearance. I thought there might be a problem with the pistons, but have redone them several times. Changing the snap ring thickness to the min wont make a difference. I bought the 6L90 trans out of a 2010 diesel ambulance with no fwd or rev movement. Fluid was not burned. I didn't check the filter for cracks which would be the most common cause. There was no metal in the pan and no obvious problems found with disassembly. Thanks Bob
Was there clearance before taking them apart? If so you must be assembling them wrong somehow. Is it a new drum? The 80s are different than the 90s. There’s a different apply ring as well. Maybe a parts mis- match. Regarding the no movement, I’d make sure the torque converter is good, make sure to check the check balls to make sure they haven’t shrunk and are in the right place, make sure there are no cracked films in the tehcm, Some have had the rear output gear shear. If you have a pressure gauge, you could verify pump pressure. I believe a sticking compensator valve can cause no movement. A gauge and checking for dtcs would likely help.
I found a snap ring improperly installed on the 3-5-R piston. Another U-tube video said that the 6L80/90 trans used a different number of steels and friction plates. Removing 1 set from the 1-2-3-4 set did the trick. The manual I bought said it was for the 6L80 instead of the "90". pictoral in the manual indicated I had too many 3-5-R steel/friction plates installed. I find it odd if the 90 is longer than the 80 why would the weaker trans have fewer plates? my freeplay is within specs now. Thanks for a very informative video. Bob
I need a press like that. I can easily make one but I need that accessory your using. I've seen one before. What is it called, maybe even a part number?
Excellent video and excellent teacher.
If you machine the bell housing what about the pump housing thickess and the vanes. You are gonna need to do something to get that .001 to .002 back. You didn't say how to fix that part?
Yes, whatever thickness removed from the pump pocket will need to be removed from the pump mounting surface. There needs to be about a .0015 gap between the rotor and slide and the pump mounting surface. Some will also machine the surface where the bell bolts to the case to keep endplay the same, but some will use the superior or sonnax shims to adjust instead.
Hola tengo un silverado 1500 2015,vivo en hollywood florida ,podria recomendarme al profesional de confianza y responsable para reconstruir mi transmision .
I got 250,000 miles on mine proper care has been done to eat it just shifts a littler hard some times any idea?
Well, the pr valve wears out so bad I’d wonder if you are getting inconsistent pressures.
What transmission vice is that? Anyone know?
Which branch speed handle is that? Is that a mac x17?
Great video! Glad I stumbled on it
Very informative. Question..what year did they change from rotational rings to non rotational rings on the pump. My buddy has a 16 truck and smoked his 6L80 good. Hardly moves. Dealer told him ya ots the converter. I droped the pan and the fluid was thin, VERY dark and smeeled extremely burnt. Magnet had so much metal and even more in the pan wasn't even on the magnet. Well I've got a 11 6L80...can I just swap the "guts"
You should be able to switch the guys. The non rotational stators were very early, like maybe 08 and earlier. So it shouldn’t be a problem. I suggest installing the transgo kits in it while it’s apart.
@@siuautomotive great info, thanks again
The dome shaped tool that you use with the screw press. What is it called and where can I find one?
6l90 ring gear is a crush fit I believe.
07 Escalade AWD trans same as 14 Silverado 4x4 besides doin a reflash..?? Thanx for any info...
It depends. The Silverado might have a 6L90, which is a bit longer than the 6L80. Plus the 14 model will have a different TEHCM, that’s an updated part number, but the plugs are the same. I don’t think you can factory reprogram one to think it’s the other.
@@siuautomotive it has MYC rpo code.. thanx again
First off thanks for an amazing educational video of the step by step. Question what rebuild kit are you using bc I have the same transmission 6L80E MYC. And I’m trying to find one that includes everything I need
I get my kits from wittrans.com. You can look everything up online, but call and talk to a salesman because it’ll be cheaper.
Thank you for taking the time to make this video. Sub'd and notified.
Damn I didnt remember writing this? :D
@@destainn I Dont either actually.
I believe there's a different piston drum, which has more surface areas on the edge of it, which allows the more pressure or easier pressure to be applied to the clutches, which is a upgrade aftermarket ,so are there other aspects of the internals which can make it stronger and last longer?
Sonnax make some performance parts for the 6L80/90. www.sonnax.com/gm_6L80_6L90
What would cause the center support to not slide all the way into the snap ring groove? I have spun the output shaft and the sprag does come down but still it won’t clear, the center support does clear with the gearset and sprag removed, if I take the Torrington bearing out it also clears, it seems like I may have a problem in the gearset? It’s a 4wd gear set and I did take it out of the output to inspect and it does go down into place but maybe not far enough? I’m at a loss and thank you in advance!
Maybe you have a bearing in the wrong spot or flipped upside down?
@@siuautomotive thank you for the reply, it seems I have the bearings all in the correct orientation (outer race down) and the bearing between the gearset and the center support pretty much goes one way, there’s and edge that sits down on the sun gear
Great video
What would cause first gear to go out completely one day and have it again the next? Did have a weird 1-2 shift under light throttle for a couple months prior. No codes btw
I messed up the copper washer and thrust washer on the low reverse sprag. Can't seem to locate those parts, Replace the whole thing?
Have you tried wittrans.com?
@@siuautomotive I have not, I'll give it a go. Thanks for the reply! I've found the video very helpful!
I could use some help. I rebuilt my 6l90 after i believe the torque converter failed. everything went good. all air checks and clearances. had to replace the pump/bell housing. rebuilt the techm pressure switches and cleaned all the metal out of everything also put in the upgraded frictions and steels, Sonnax zip kit, put it all back and the pressure looks great. but now i have 3 fault codes (p0989, P0872, P0877) Low voltage on the transmission fluid pressure switches 3, 4, and 5. Reverse seems to be delayed, as well as shifting from 1st to 2nd and 2nd to 3rd. 3456 seem fine. Any help will be greatly appreciated.
Many times you'll need to replace the tehcm after a converter failure. That junk gets into everything. Did you use a tool to place the pressure switches? I know those pressure switches can be a pain at times, but they are essential to the operation of the trans. If any fluid pressure can get behind those switches, it'll throw codes and not work correctly.
Lastly, did you replace the radiator or bypass the radiator with an external cooler? After converter failure, all that junk ended up in the radiator and likely plugged it. It's hard to get that out without a good flushing machine like a hot-flush.
@@siuautomotive I did use the tool for the switch rebuild. I air checked them the best I could. I used 3 cans of kooler kleen to flush the lines. Looked good in-between the 2nd can. I did clean the seperator plate with a wire wheel to get the bonded gaskets off. Kind wondering if that was a bad idea.
@@siuautomotive the low voltage at the switches has me puzzled though. Seems switch 2 is fine. Only 3,4 and 5 has the code.
There is no switch two. I don't know why they skip 2, maybe it's something internal to the TCM, but switch one is for the 35R, switch 3 is for the 2-6, switch 4 is for the 1234, and switch five is for 456. If the codes are for low voltage, then the switches are stuck in their "normal" position, because when the switches ground, they allow current to pass to ground and the voltage is dropped in the TCM through an internal resistor. The switches kind of work opposite then you'd expect. They don't have pressure in the gear they are representing. So switch one won't have pressure (thus make contact and show low voltage) in Rev, 3rd, and 5th. I have an electronics presentation for this on RUclips as well.
Also those cans of cooler cleaner won’t get it all. Shops that use the hot flush will run it for an hour and still get stuff out of the cooler. The hot flush uses heated fluid and reverse pulses when it’s flushing to jar out the debris. If I had converter damage and I didn’t have a heated flusher that can reverse pulse, I’d either bypass the radiator cooler with a large air to oil cooler, but only if I lived in warm climates. If you have cold weather, it’s best to just replace the radiator.
Please help lol!! I rebuilt my 6l80 I did air check all gears holding except compensator feed should it hold air like the clutches and gears I understand how it works just not sure if it should hold air did the test no converter , tail housing or valve body
I don’t believe the compensator will air check as well as the clutches. When you rebuilt the trans, did you change that bearing in the 3-5-R/1234 drum? It has a seal built into it to seal off the compensator passage. If that’s installed incorrectly or the seal is damaged you’ll get a worse air check.
How much can I expect to pay for a job like this my 2018 Chevy Silverado 1500 rwd is shifting hard in low gears
It’s hard to say, but 3500 is pretty common for an overhaul. Maybe 4000 if they change the techm.
on my 3rd 6L80e they all worked great except this last one kicking my butt. Just as soon as I hit 4th gear I'm getting this whooooooooo noise with some weird grinding noise attached. it goes away as soon as I let off but comes back as soon as I reapply. I see nothing abnormally worn. all my clearances are within specs. Pistons are good. I suspected a bearing but they all feel decent! I'm struggling with this one. My planets look good! What do you think it is? It's only after 4th applies....Same noise before the build. same noise after the build. Hd converter. new pump assembly. new blue Pistons clutches and steels. changed rubbers and laminates in computer. no codes
So does it work in 4th? Or is it slipping? Just trying to mentally picture what’s going on.
@@siuautomotive it's working in 4th. after the build I drove it maybe 15 miles. I tore it back down and didn't see any excessive wear on the clutches. Ive searched this problem online and have found alot of guys experienceing and describing this same noise. Thanks for your time btw. thank you it's not slipping into 4th it falls into 4th and immediately noise let off the gas it goes away apply the gas noise with a weird grumble attached. I see nothing. I put it under the microscope all hard parts
@@siuautomotive I did find since it's a 2017 that I reused the number 8 check ball the undersized one. I put it back in it's original spot. the transgo instructions tell me not to use the undersized check ball. I'm going to change it to . 250 and see what happens
What would cause the torque converter not to get fluid
The pump isn’t picking up fluid. Maybe cracked or clogged filter. The pressure regulator valve could also be stuck.
You have the best transmission stand I have ever seen. Did you invent that yourself?
No sir. It's an old GM tool (kent-moore). They still sell them, but they are pretty expensive. There are other options, like this one from adapt-a-case: adaptacase.com/t-48909ac.html or this from ATEC trans tools: www.toolsource.com/holding-fixtures-and-support-c-1321_119_582/gmtransmission-holding-fixture-t0156b-wo-base-p-94383.html?tsqtid=809059
Hello sir! I got a 6l90 from a online parts place.they claim it got 45k miles. I pulled the TC out and got black color oil spilled. That got me wondering-did i get a really burned up unit? I never seen a transmission with black oil. Or its something new i don't know about?
Thanks
Hmm, black oil doesn’t sound good. Does it smell burnt? I would take it apart and freshen it up and put a transgo kit in it.
@@siuautomotive it does smell burned. The fact is that i bought it as a low mileage (45k miles) working unit. But its been more then 30days. I will try and claim it as a loss with my credit card bank..
Any idea what would cause a 6L80 to “fall” out of 1st gear idle and “snap” into 1st gear once the rpms get to 1,500(doesn’t consistently happen). But only on shift pattern X and Y. But Tap shift commanded 1st or 2nd no issue
The low sprag slipping could cause this. I’m not sure, but the pcm might leave the l/r clutch on when tap shifting. The low sprag and l/r clutch holds the same component.
Where can I get this tool ,for application Whit air the drum
In the video I have a close up of the tool that's made by someone else. He has his phone number on the tool.
Your excellent teacher
Hi hoping can help me, I'm using a GM LS2/LS3 Engine controller kit p/n:19354328 and want to run a 6L80E transmission, can you please advise what trans harness I would need to work with p/n:19354328?
Sorry, I don’t know that answer. You might post to the forum on hptuners.com and see what they have to say.
Hello. Great video! It was such a great tool for reference.
When doing an air test after a rebuild, all gears test good. However, the compensator doesn't hold pressure and leaks quite a bit. Is this normal? If not, can you recommend a starting place to look. Thank you!
I guess it depends if you have that tool for checking the 3/5/R drum. The compensator passage is found under that bearing on the drum. That needle bearing has a green seal built into it. If you didn't replace that bearing, it might be leaking from there. If you did replace the bearing, you might have installed it upside down if you didn't notice the seal.
@@siuautomotive I'm testing at the pump port with the transmission assembled and the valve body removed. I did not replace the bearing in the drum as it was not included in my trans star kit. I received a note in the kit stating there was shortage and they could not supply it at this time.
Thank you! I'll take a closer look and let you know what I find
I was able to find a new 1234 35r drum bearing/seal today and replaced it. It is correctly installed. Testing it as I described after changing it still doesn't seam right. I do not hear any sort of engagement, just air moving through the transmission. It will hold pressure for a moment but leaks out rather quickly. Any other suggestions that come to mind? I don't know what other drums it travels to. Finding a solid diagram to understand the system has been difficult. Many thanks for the help!
What rebuild kit did you use for the clutch plates and steels?
I use kits from Witrans.com, transtar1.com or slauson.com. Also check the dealer, because sometimes their kits are cheaper. Download and signup with repairlinkshop.com to check dealer prices and availability.
@@siuautomotive great thank you! Very informative in your work! Thank you so much for the reply and the knowledge you give away! Keep up the great work brother!
In the 6L90 with 178k miles, what causes a 1 to 2 hard shift and a slow responding shift to reverse? Also got a pulsing feeling in 1st or 2nd. Parked it since and going nuts.. This happened after I let truck sit for a week when I usually drove it everyday. Any help is appreciated.
Are there any DTCs stored? Pressure switches are common failures and they cause all kinds of problems, but you usually get a DTC. The 3-5-R housing cracks and that could be your reverse issue. The pumps really wear out the pressure regulator bore and that causes high and unstable pressure, which could cause your harsh shift and could also cause the crack in the 3-5-R drum. Not to disappoint you, but that's pretty much the mileage people get out of this trans before it needs an overhaul.
@@siuautomotive no codes. I changed filter and fluid which was dark and had some fine flakes of metal. Forward gears felt fine after but reverse still lags sometimes. Looks like I'll be looking for a replacement
Just had mine overhauled at 160k it was always a hard down shift to first gear always shifting funky now it’s like butter I hope it stays that way I got 3600 in mine 🥹it hurt it still hurts I’m sitting on one cheek still
I have a 09 6L80E 4x4 with codes P0700,P2723 and P2771 would you recommend a full rebuild or solenoid assembly
If it has more than 100k miles, I'd say it's worth your while to rebuild. They do have pressure switch issues, and simply fixing the pressure switch films might fix your codes, but that P2723 is related to the 1234 clutch and that piston is known for cracking.
@@siuautomotive Thank you. Now to find a reputable shop locally.
What would be the cost of a new 6L80 made to be as strong as a 6L90, but with out the center driveshaft ,so can it be done, to make the 6L80 as strong as the 6L90, only because the 6L90E is longer and stronger, what can be done to make the 6L80E just as strong as the 6L90E but without turning it into a 6L90E longer unit?
The 6L90 has one more input clutch and one more holding clutch, plus the rear gearset is more stout. I don't know if it's possible to make the 6L80 as strong as the 90. TCS sells a upgraded rear planet, but aside from modifying pressures and maybe putting in performance clutches, I don't what else one could do. Thanks for watching the video!
Hello how you doing, I have an issue with a 2014 Chevy express 3500 ,6l90 trans. The issue is when your going 70mph you put the cruise control on then when it down shift from 6th to 5th, it won't release the 6th gear what so ever, the same shifting down and up manually, please help any idea what could be wrong.
Any idea what could it be thks.
I'm not sure what you mean by "it won't release 6th gear." If 6th gear stayed applied, it would bind up and feel like someone hit the brakes. The transmission wouldn't last long if this were happening. If you mean that when it downshifts to 5th gear the engine flares up, then it might be an issue with the 3-5-R hydraulics. The 3-5-R clutch housing is known to crack. These transmissions also have issues with their TEHCM (control module and solenoids), so it might be something to do with that.