I'm asking for my brother in-law... neways his trucks a 2004 sierra has a lb7, 4x4. Mods are as fallowed. S&b intake, mbrp 4" exhaust, edge juice with attitude, 50hp injectors, bd super max turbo.

His truck before the turbo and the injectors would run fine on any tune setting. Now on the higher tunes it seems as if the tranny is slipping or something but only does it sometimes. It will take off hard shift 1-2 but lag 2 seconds or so and do the same 2-3. It ran fine before the mods and only does it on the higher tunes. it would make since with the power to have it slip but it almost feels like it defuels. To me it almost feels like the converter is spinning or something ? Any ideas thanks guys

 

Time for a built trans most likely. My '01 can limp a trans, and it's tune only.

IIRC, Edge tuning will de-fuel if any trans slip is detected.

 

Yeah , stock converter and trans only like 75-100 extra horse power , plus switching between tunes is hard on the Allison as it has adaptive shift learn ( drive Like a grandpa it will shift like grandpa , then start to beat on it and it flares till it learns hard shifting).

Edge tuning is crude and not smooth at all on power delivery . I had edge juice/attitude/ hot unlock on my LBZ, hated it .

Smoothest and best power was with EFI live custom tuning , and also the PPE hot +2 et eliminator , shifted nice !

Also the more you limp a trans the easier it is to do it .

So get better tuning and build the trans / converter if ya want big power , if not don't turn up the tuner for now . Also keep a clean fuel and spin on trans filter on these rigs as they will affect shifting also.

 

couldnt of said it better tim!! and the 5 speeds r weaker in stock forum then the 6speeds and the lag between shifts is its defueling itself to save itself. he needs a stg4 or 5 trans a triple disk converter and it'll never happen again!

 

Nail on head!

 

OK cool guys. I'll pass it on. You think even a efi tune or something can make a difference until he can afford to get a tranny?

 

The tuning would likely be better. But it will still be able to kill the trans on higher power levels.

Conservative driving is really the only thing that can extend the life of his trans.

 

Making more power than stock trans likes. That's why they are so detuned from the factory.
Time to bust open the piggy bank and invest in more supporting mods.

 

This is where you need to start....
TransGo SK Allison Shift Kit
Other handy things to get will be a nice multi disk torque converter and down the road a sun coast rebuild kit.

 

If the tranny is already slipping which it most likely is cuz it's defueling itself the shift kit is pointless at this time it just need to be completely rebuilt.