I have owned my 04 Sierra 3500 dually for just over a year now, its a great truck, but came with no manuals. It came with a Whipple Supercharger installed w/ the Allison. Having no prior knowledge (or current) of these trannys, I have some questions.
First, are they kind of jerkey, especially when cold.
When I shift from D to P it will sometimes get held up in R and when I push past into P it will jerk the entire truck around, and the drive shaft will make quite a bit of racket.
Also, it seems that the tranny will never quite be in neutral, even when in nuetral, it will still want to roll foreward as if in gear.

I had read on the Allison web site that they are now recommending that the fluid be replaced after the first 3,000 miles, then normal incraments after that. I have not changed it yet (36,000 miles) Could this be the problem?Or could the supercharger be effecting it, with the intercooler working the engine temp. never gets above 180.
Also if anybody has any experiance with the supercharger. To check the tranny fluid is nearly impossible with the air ducting in the wayof the dipstick, any suggestions?

Thanks for any help

 

Welcome to the forum!!! May want to post your question in the Sierra section if you haven't already.

 

Sounds like the linkage for the shifter might try to Email them and ask if they have had any problems before let them know that you bought it as is. As far as the supercharger that will not effect youre trans and the dipstick prob is just something the person that added it was just going to live with guess.