Allison Transmission Questions
Help Mr Allison Help,
I have a Chevrolet 2002 Duramax with the Allison transmission, This is a C2500 four wheel drive extended cab pickup and up until now I have had no trouble with the Allison (in fact its a great transmission) The problem goes like this I now have about 102,000 miles, the truck has always been serviced by the dealer at the appropriate times including the transmission. While driving down the road somewhere around 62 mph all of a sudden the engine just revs up, as I release the throttle you can feel the transmission catch or take control again. This happened about six times on Monday and Tuesday morning while enroute to the Chevrolet dealer it was worse. Before I made it to the Dealer it would not shift into overdrive and as I came to a stop about a mile before the dealership, I heard like a loud breaking glass noise or grinding glass noise, as I pulled into the dealership the breaking glass noise was gone.
The dealership called today Friday and said it was fixed, that a module had to be replaced. To replace it they had to pull the transmission back a bit from the engine to get to it, well thats what they said anyway, and explained to me the computer had put the engine/transmission into what they called limp mode (when it would not shift into overdrive) I picked up the truck and was told that the tail piece needed a seal that it had a very minute leak and they ordered the seal but I could go ahead and use the truck until next week when the part comes in, I offered to pay the bill and the service manager said Terry the part was only twelve dollars lets just wait until we finish putting in the seal, which I thanked him. Driving away from the dealership I had thought this was a very serious problem, I was so relieved it was not.
Well after driving about ten to fifteen miles it started again around 62 mph it just like slips out of gear and the RPMS go way up and you hear the roar of the engine I let up on the accelerator it like takes hold and works ok for maybe four or five miles and then again the same thing.
I really want to get this fixed but I don't know where to take it, I am sacred to go to like a transmission rebuild shop and I really don't think the dealership techs are all that great either. When I arrived at the dealership we checked the fluid and it was clear with a red tint and had no burn smell whatsoever so I need someone with words of wisdom. Thank you in advace for your help. Just for your information, I tow with this truck seldom and when I do it is a light small trailer. I do not know anything else to add to this with the exception that yesterday when I went by to get some tools out of the truck they had I think two hydraulic hoses hooked to the transmission but where they went to I have no idea other that they were very long.
Thanks again
Terry Shrum
Tulsa, Ok
