LAGA

I found a dyno tuner just outside Chicago, Finish Line Performance. I talked to them in person and will be going to have them tune my 07 NBS VMAX, with the 4l70E trans. MY question, the tuner I talked to suggested we leave the line pressures for the trans at stock levels, is this the right thing to do? I have done a lot of reading on both custom tunes and mail-order tunes and most either raise line pressures or install a shift kit. Which one is better? Are either necessary? The truck is a daily driver that does not tow. Thanks

trever1t

iTrader: (14)

Don't know the answer but I'll bump this question ttt!

95ImpSS

iTrader: (2)

If you don't want to go to the tuner, a shift kit would give you what you're looking for w/o the cost of a tuner. If you wish to pay the tuner, hope you don't have issues that warrant reflash of PCM by dealership. If that's the case, the tune's lost anyhow. Trans upgrade could extend the life of the trans though.

Maybe the two trans sponsors will pop in and comment... FLT & Performabuilt. Good luck!

LAGA

I am getting the tune to improve the performance of the truck. I would like to get opinions on what is best for the life of the trans.

95ImpSS

iTrader: (2)

if just an opinion, then shift kit & Sonnax servos.

performabuilt

iTrader: (24)

Shift kit and corvette servo. I am not real big on cranking the line up i tuning either.

FLT

iTrader: (1)

Did you talk to Dan Bills? He is a very good tuner and you will be happy with his work. As far as the question on the pressures that is a flip of the coin. I prefer the shift kit route instead of elevating them in the tune. But as mentioned that can void your warranty. Vince

06sierra5.3

iTrader: (7)

my shift kit was def. worth it. i was told if i was going with the shift kit then to leave the transmission line pressures stock.

LAGA

I talked to Mitch. He said leave the line pressures alone. Bottom line--- does a shift kit protect a trans when you increase engine power and torque or does it lead to premature failure? Any info Is needed as I know nothing about transmissions.

BlackGMC

iTrader: (31)

If you get a shift kit make sure your tuner zero's out your shift times in the tune, otherwise the quicker shift that the shift kit provides will cause the computer to think it is shifting faster than it is supposed to and actually lower your tranny pressures to compensate for the faster shift and try and slow it down...