My Son's 02 G.M.C. with the Duramax and Allison, acted wierd yesterday. He was driving in tow mode,pulling our 16FT. trailer. Going about 60 MPH. when the tranny down shifted to 4th gear,amd went to tourque instead of lock-up. He limped home,and then had no reverse. The SES light came on but only for a couple minutes,then went off. He let it set for awhile, then tried it and everything is fine today. I'm thinking maybe the NSBS is the problem, but could use all the advice I can get. Thanks

My Son's 02 G.M.C. with the Duramax and Allison, acted wierd yesterday. He was driving in tow mode,pulling our 16FT. trailer. Going about 60 MPH. when the tranny down shifted to 4th gear,amd went to tourque instead of lock-up. He limped home,and then had no reverse. The SES light came on but only for a couple minutes,then went off. He let it set for awhile, then tried it and everything is fine today. I'm thinking maybe the NSBS is the problem, but could use all the advice I can get. Thanks


Limped home, Limped being the key word here.

Limped home, Limped being the key word here.

so you are thinking the tranny might have limped, then reset itself.

Thats what it sounds like.

exactly what happend to me the other night. no reverse, and would have to give it alot of gas to get going. i got code p0700. I turned the truck off and let it sit for a while. its been fine for 3 days now. code is gone.

Sounds to me like 'sonebody' might just not be using just the 65hp setting..:rolleyes:.. Find out the niddy griddy and you just might have to wait and see if the c3's are a lil' burnt.:eek:..

Thanks for all the help. I found out he was passing a line of cars in a passing lane when it happened. Passing was'nt bad ,but with the trailer, it was'nt a good idea. Ahh to be younger and full of he;;.

I have had this happen a few times, the dealer keeps saying it is the park/neutral switch.