Description and some info about how the Caterpillar 7155 transmission works and how to drive it. These are found in the M915, M916, M917, m918, m920, etc.
37th Group, 28th Trans, 150th here from old Spinelli Barracks, Mannheim. Had so much fun back then. Hauled commissary, ammo, missiles for the INF Treaty, caskets for crew members of the U.S.S. Stark and I was on the team that distributed the new M16's across Germany with a small, german civilian team. LOVED IT!
Enjoyed your video, I was in the Army at Ft. Benning GA from '86 to '90 in the 533rd Transportation Company, we had 46 of these trucks in the M915 variant. 3 platoons of 15 and 1 truck for the maintenance platoon with a Holmes wrecker kit on it, I was the wrecker operator. Loved these trucks, loved that sound of the air solenoids. We all got pretty good at driving them too. Don't know if you knew this or not but a M915 would do an 1/8 mile in 11 seconds.
So didn't I ..... Ft. Lewis Wa. [79 to 81] We traded in our M52A2's &M818;s for the M915 in 1980 ....... 513 th Trans.Co........ P.C.S'd to Kaiserslautern , Germany early in 81' ...Kleber Kaserne ... 89th T.C. 53rd Bn. 37th Trans. Group ..... A couple of P.C.S,s and I was back in 53rd Batt , only in 66th Trans Co. this time around . Had roughly 60,000 or so ......
Thank you. I appreciate it. I plan on making a better video with some more info in it. Yeah the original 5th wheels on these are tall. I'm 6'2" and it was about eye level. They also take a 3 in king pin.
You forgot about the M919 which is a concrete patch rig. The first variants of M915A0's-M920A0's all had the 7155 Caterpillar.They went to the Allison Automatics starting with the A1's.I have one and all I've done is replace the governor spring so that it's not stuck at 57 MPH.Mine currently has 636,390 miles on it's NTC-400 and it's aftermarket with more than 500 HP/1,950 TQ
ntc-400 does not have 1950 torque, Pittspurgh power told me the cummins 855 are not torque motors, they told me an 855 turned upto 500 hp is still less than 1500 torque. they like to rev but not torque.
@@davidroberts6594 Cool story...Now do us a favor and learn how to read because I obviously put "aftermarket" when talking about the power from my NTC-400 in my truck. NTC-400's are 400 HP/1,200 TQ when stock. They like to rev? If you want to be a internet expert about 855's,take a look at the NHC-250's.Those engines destroyed bearings and valve seals over 2,100 RPM even though the military issued TM's stating they could do 2,300 RPM.This was back when the five ton trucks still had them.And that wasn't the entire list once fragile rocker arms and weak cams are mentioned.
They are a cool transmission and have put a lot of miles on them , but you have to know how to shift it and you never let the RPMS drop below 1150 rpm as these transmissions have a centrifugal clutch and if lug them it WILL damage the clutches.
My military unit in Germany had a lot of trouble with the valve group gumming up...untill the old alchole air drying system was replaced with a modern indesece style dryer... If your truck is still using the alcohol bottle under the hood...please invest in a new air dryer system
I have a video posted on my page on how to do the selector bypass that allows the 2 gear jump all the way to 16 without having to use the inhibit lever
Good video. How are things working out with that truck now that it's three years later? I'm looking at purchasing one and just have concerns about the durability of the transmission and ease of repair of the unit. I plan on using it to haul construction equipment around the mountains of Utah so it would seem to be the ideal setup.
So the one thing I didn't quite grasp is, what's the purpose of the "button" that acts as (to what I could tell) a 'clutch'? I noted you shifted without it while in motion.
Not sure what you're asking. There used to be a pedal on the floor that you used with your left foot to turn on the Jake brake. I removed it and installed a switch on the dash. Is that what you're asking about?
Nicely done video! Cool trucks and a awesome transmission. Drove the M916 in the Army in the 80's, I liked the 7155 so well I put one in my 1996 Western Star 2 years ago and have thousands of miles on it now. Basically drive it like you are floating a manual. I moved my Jake to the floor, but I understand your reasoning. So are you going to put a fifth wheel back on after the stretch or are you building it into something else?
ponway . That's awesome! I hadn't heard of anyone installing the 7155 such as you described. It is a neat transmission. As far as my m916 I will be putting the 5th wheel plate back on. Possibly a sleeper as well.
The air ride and longer wheelbase ought to be a big improvement in the ride! I see one of my friends has posted a short video of a ride along, if you search "7155 western star" you should be able to find it. Took a while to get all the parts together, I didn't just take it out of another truck. Did the work myself. If I get back out that way, maybe I could stop by and show it to you! I'm in Indiana.
Yeah definitely. If you are ever near Boise idaho let me know. Do you have a line on any parts for the 7155? I can find the solenoid box at a few different military surplus places, but I would like to find other parts. Such as seals and the clutches.
@@ponway hey sorry. I had gotten a new phone and I wasn't signed into RUclips. I did get your emails. Thank you. I had thought I replied but I'm sorry if I didn't. I'm not looking for any 7155 parts, but like to know where I could get them if I ever need any.
I haven't done anything with my truck yet. On that 917 try putting some air tool oil in the main air line that runs into the transmission. Sometimes that can loosen up the sticky shift solenoids.
I've had to do that a few times in mud. It's actually not too bad. From my experience it's about the same rocking in and out with a 13 or 10 speed. It's not like the modern auto shifts they have now. Those suck because you have to have your foot on the brake to get in and out of forward and reverse. These 7155 transmissions......what ever gear you place it into, at any time, any speed, any rpm...........it's going to go into gear so be ready!
moving the jake from the floor to the dash your loosing its advantage,i drove these trucks in germany and ft lewis,i have a metric shitton of miles shifting these,the foot pedal jake makes it very easy to coordinate the jake with the trans
@@prodieselrepair3218 i was at ft lewis washington as well,lots of 7% grades for 7/10 miles,holding the pedal down really wasnt an issue for me but your rite everyone has the preference
37th Group, 28th Trans, 150th here from old Spinelli Barracks, Mannheim. Had so much fun back then. Hauled commissary, ammo, missiles for the INF Treaty, caskets for crew members of the U.S.S. Stark and I was on the team that distributed the new M16's across Germany with a small, german civilian team. LOVED IT!
Enjoyed your video, I was in the Army at Ft. Benning GA from '86 to '90 in the 533rd Transportation Company, we had 46 of these trucks in the M915 variant. 3 platoons of 15 and 1 truck for the maintenance platoon with a Holmes wrecker kit on it, I was the wrecker operator. Loved these trucks, loved that sound of the air solenoids. We all got pretty good at driving them too. Don't know if you knew this or not but a M915 would do an 1/8 mile in 11 seconds.
i have a lot of miles shifting one of these in germany and ft lewis!!! 88-mike whoaaaah
So didn't I ..... Ft. Lewis Wa. [79 to 81] We traded in our M52A2's &M818;s for the M915 in 1980 ....... 513 th Trans.Co........ P.C.S'd to Kaiserslautern , Germany early in 81' ...Kleber Kaserne ... 89th T.C. 53rd Bn. 37th Trans. Group ..... A couple of P.C.S,s and I was back in 53rd Batt , only in 66th Trans Co. this time around . Had roughly 60,000 or so ......
@@1959hogryder i was in 513th 1992 1994,thats awsome
I used to love the shift sound. 8th engineer our 916 had a crane mounted on it
I added a filter regulator luber to the air supply for trans to keep the shifter lubricated, based on what i read on the forums. I have a M920.
Definitely A one a kind transmission especially mated with a Big Cam Cummins NTC 400.
I was using these in the Army in 1996-1999
This video answered all my questions and informed me of more than I expected. I always wondered about the height of the 5th wheel. Good job!
Thank you. I appreciate it. I plan on making a better video with some more info in it. Yeah the original 5th wheels on these are tall. I'm 6'2" and it was about eye level. They also take a 3 in king pin.
Awesome video man ! Appreciate it.
Thanks. I'm planning on filming a new video that isn't so long and boring. Same info (and more), half the length, and not boring
You forgot about the M919 which is a concrete patch rig.
The first variants of M915A0's-M920A0's all had the 7155 Caterpillar.They went to the Allison Automatics starting with the A1's.I have one and all I've done is replace the governor spring so that it's not stuck at 57 MPH.Mine currently has 636,390 miles on it's NTC-400 and it's aftermarket with more than 500 HP/1,950 TQ
ntc-400 does not have 1950 torque, Pittspurgh power told me the cummins 855 are not torque motors, they told me an 855 turned upto 500 hp is still less than 1500 torque. they like to rev but not torque.
@@davidroberts6594 Cool story...Now do us a favor and learn how to read because I obviously put "aftermarket" when talking about the power from my NTC-400 in my truck.
NTC-400's are 400 HP/1,200 TQ when stock.
They like to rev? If you want to be a internet expert about 855's,take a look at the NHC-250's.Those engines destroyed bearings and valve seals over 2,100 RPM even though the military issued TM's stating they could do 2,300 RPM.This was back when the five ton trucks still had them.And that wasn't the entire list once fragile rocker arms and weak cams are mentioned.
Awesome informative video.
They are a cool transmission and have put a lot of miles on them , but you have to know how to shift it and you never let the RPMS drop below 1150 rpm as these transmissions have a centrifugal clutch and if lug them it WILL damage the clutches.
My military unit in Germany had a lot of trouble with the valve group gumming up...untill the old alchole air drying system was replaced with a modern indesece style dryer...
If your truck is still using the alcohol bottle under the hood...please invest in a new air dryer system
I have a video posted on my page on how to do the selector bypass that allows the 2 gear jump all the way to 16 without having to use the inhibit lever
Good video. How are things working out with that truck now that it's three years later? I'm looking at purchasing one and just have concerns about the durability of the transmission and ease of repair of the unit. I plan on using it to haul construction equipment around the mountains of Utah so it would seem to be the ideal setup.
So the one thing I didn't quite grasp is, what's the purpose of the "button" that acts as (to what I could tell) a 'clutch'? I noted you shifted without it while in motion.
Not sure what you're asking. There used to be a pedal on the floor that you used with your left foot to turn on the Jake brake. I removed it and installed a switch on the dash. Is that what you're asking about?
Nicely done video! Cool trucks and a awesome transmission. Drove the M916 in the Army in the 80's, I liked the 7155 so well I put one in my 1996 Western Star 2 years ago and have thousands of miles on it now.
Basically drive it like you are floating a manual. I moved my Jake to the floor, but I understand your reasoning.
So are you going to put a fifth wheel back on after the stretch or are you building it into something else?
ponway . That's awesome! I hadn't heard of anyone installing the 7155 such as you described. It is a neat transmission. As far as my m916 I will be putting the 5th wheel plate back on. Possibly a sleeper as well.
The air ride and longer wheelbase ought to be a big improvement in the ride!
I see one of my friends has posted a short video of a ride along, if you search "7155 western star" you should be able to find it. Took a while to get all the parts together, I didn't just take it out of another truck. Did the work myself.
If I get back out that way, maybe I could stop by and show it to you! I'm in Indiana.
Yeah definitely. If you are ever near Boise idaho let me know. Do you have a line on any parts for the 7155? I can find the solenoid box at a few different military surplus places, but I would like to find other parts. Such as seals and the clutches.
I sent a message to you that might help you out. I used the email address on your business card.
@@ponway hey sorry. I had gotten a new phone and I wasn't signed into RUclips. I did get your emails. Thank you. I had thought I replied but I'm sorry if I didn't. I'm not looking for any 7155 parts, but like to know where I could get them if I ever need any.
How do these compare to the M35a2 in the area of reliability and ease of maintenance?
Apples and oranges...
Whats the latest on this truck? Ive got a 916a2 and a 917a0. 917 will not go in any gear.
I haven't done anything with my truck yet. On that 917 try putting some air tool oil in the main air line that runs into the transmission. Sometimes that can loosen up the sticky shift solenoids.
If you were to get stuck and needed to rock your rig in snow mud how well would this 7155 do switching between forward reverse over and over? Thanks!
I've had to do that a few times in mud. It's actually not too bad. From my experience it's about the same rocking in and out with a 13 or 10 speed. It's not like the modern auto shifts they have now. Those suck because you have to have your foot on the brake to get in and out of forward and reverse. These 7155 transmissions......what ever gear you place it into, at any time, any speed, any rpm...........it's going to go into gear so be ready!
What do you do when you roll up to a light? Can you leave it in gear or do you have to go to neutral for that?
Leave it in gear..
We bought an m920 for hauling manure, and was wondering if there is a certain rpm you need to be at when shifting?
Not really. The transmission doesn't care. Just avoid lugging or over revving the engine
never let the engine go below 1100 under load or it will slip/burn the input clutch.
moving the jake from the floor to the dash your loosing its advantage,i drove these trucks in germany and ft lewis,i have a metric shitton of miles shifting these,the foot pedal jake makes it very easy to coordinate the jake with the trans
To each is own. But when you go down 7% hills that last 10 miles or so I hate holding my foot on the pedal that long
@@prodieselrepair3218 i was at ft lewis washington as well,lots of 7% grades for 7/10 miles,holding the pedal down really wasnt an issue for me but your rite everyone has the preference
Whoever called me from a 306 Canada area code try me again. I tried calling back , but my phone plan doesn't let me make the call
Did you tee your air line in for the rear clutch gauge where the jake pressure switch is?
No on the back of the solenoid block there's a port used for checking air pressure for the rear clutch. I just removed the plug and used that.
Motor grader transmission
Cummins engine and a cat transmission lol
Un camion fantastico ❤