Have an 06 QC 4x4 diesel automatic. Have about 85K miles and it's bone stock. Maybe 30,000 miles ago I noticed that sometimes when I floored it and the trans downshifted it would slip for a few seconds before everthing locked up and I accelerated. By slip I mean the motor revs and there is no acceleration. Over time this happened more frequently and the lag time increased. Today I was towing about 9,000lbs and again while downshifting the motor revved and nothing happened for a good ten seconds. Any downshifts even part-throttle were not locking up. Once I unhooked I tried again and same thing. Now it won't even upshift unless I am babying the throttle. The fluid level is correct. I have changed the filter and fluid regularly. I have also done the complete fluid exchange at the dealer. Anybody know what could be causing this? Have I ruined this trasnmission?

 

you dont need a new tranny just do a torqu converter and valve body on the one ya have

 

Sounds like mine

 

How much extra juice you running through the CP3??

 

So you think I broke one of the two or maybe both?

 

you over powered it and slipped the bands.....its done now

I would have Georends go thru it and to the TC and VB

 

So the bands are bad too? Sorry for too many questions. Not sure what I am getting myself into here and need advice on exactly what to do. Can I do this work myself? I have experience with engines and suspensions but have never touched an automatic transmission.

 

an auto tranny is one thing I would take to a shop......I am a mechanic and do all my own work too but I would still take it to the pros.............thats just me

 

There are a LOT of little things to building an auto to handle the Cummins. You are much better off getting it done by an experienced builder.

You will really like the results.

 

Yeah. Sounds like its time for a trip to the shop. If you rebuild a stocker, think about an aftermaket valve body and converter. If you are not pushing more than 150 hp / 350 tq with power upgrades, you should be fine. Just be careful should you start pushing serious power.

Your stock tranny will start to break internals.