2011 Allison Transmission Surging

[demcoinc4]

My 2011 2500HD Duramax has 20K miles on it. Twice now, when I shifted it into gear, reverse or drive, it surges and I can't stop it with the brakes. I have to shift it into nuetral. The first time to the dealer, they informed me a code was set for the Torque converter was locked. So that means it was like direct drive. They cleared the code, added a software update and sent me home. One week later, exactly, It did it again. I was out of town. It was a 10 hr trip with no events. When I started my truck the next morning, it did it again with no warning. I shut the truck off, restarted and the same thing. In drive, it would stall the engine. I shifted it to 1st gear, drove around the parking lot, shifted back up to drive, and it was ok...hmm. I called the dealer again. They suggested if it is ok now, bring it in when I get back home. I did, there were no codes this time. They kept the truck over the weekend, claimed they drove it and couldn't duplicate the problem. They said they performed a transmission relearn that was from GM. They gave me the truck back and said it should be good. Its been one day. so far, no problems though it still feels like it shifts a little weird like I've noticed since the problem first started. Hard downshifts just below 40 mph and very hard downshift just befor stopping at light. I cant let my wife drive it for fear of this happening again. I'm not satisfied with this fix. I feel it will happen again, so I park accordingly for now. Anyone out there here of this before????

[markw8]

Your going to have to keep driving it and see what happens. With a relearn, it will take more than a few miles. They are very good transmissions. It might never happen again.

 

Mark

[07sierra8.1]

My allison does this too i got the 8.1L though...idk what causes it...doesnt always do it...i never worried about it, it will really do it if you have it in 4LOW though...almost cant stop the truck at all

[demcoinc4]

It's done it a couple of times since my last visit to the dealership. One time last Saturday with my wife driving it...needless to say, she freaked out! When it does it, it will keep doing it as long as I don't shut the truck off. So I was leaving the house Tuesday morning and it did it. So first off, I had my wife come out with the camera and video my putting it in gear. Got some good footage. So I left, without shutting the truck off, and headed for the dealership and, YES!, when I got there, it was still doing it so they could "duplicate" the problem. They are in contact with GM and Allison and waiting for some instruction. They said Allison may want to replace with a new tranny and take this one to the engineers bench. They claim this is an isolated problem and they want to figure out what's causing it. Meanwhile, I am driving a 1/2 ton pickup from the dealership. Hopefully they come up with an answer soon.

Thanks,

[8100 Power]

It's done it a couple of times since my last visit to the dealership. One time last Saturday with my wife driving it...needless to say, she freaked out! When it does it, it will keep doing it as long as I don't shut the truck off. So I was leaving the house Tuesday morning and it did it. So first off, I had my wife come out with the camera and video my putting it in gear. Got some good footage. So I left, without shutting the truck off, and headed for the dealership and, YES!, when I got there, it was still doing it so they could "duplicate" the problem. They are in contact with GM and Allison and waiting for some instruction. They said Allison may want to replace with a new tranny and take this one to the engineers bench. They claim this is an isolated problem and they want to figure out what's causing it. Meanwhile, I am driving a 1/2 ton pickup from the dealership. Hopefully they come up with an answer soon.

Thanks,

 

Sounds like the TCC isn't disengaging. Hopefully they'll figure something out as that can be dangerous. Let us know how it turns out! Good luck.