Dyno Tune And Transmission Question

LAGA · March 15, 2008

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

Schmids5.3l · March 15, 2008

I wish I knew more about the NNBS trucks. I'm getting dyno'd here in a week or so hopefully. The shop recommended me a 1-2 Corvette servo, and some other random small stuff that I ordered. As for raising the line pressure vs a shift kit, I have no idea. But, a quick/fast shift is were it's at, as it will result in less heat and less slippage.

In reality these 4l60/65/70's are nothing more than 700R4's that GM has been fiddling with for 25+ years, IE not the ideal transmission for a heavy truck/Suv with lots of power, they are barely rated to handle factory power and use torque management as a crutch.

If you do some google searching of 4l70e you'll find lots of info, especially on our sister site, www.silveradoss.com. That Vortec max is really going to move with a dyno tune

ridnlow · March 15, 2008

Without a shiftkit you could up the pressure some.. with one, run the stock pressures..Also the guys at Finish Line Transmissions used to work for Finish Line Performance and they know a thing or two about transmissions, so I would take whatever advice they are giving you!

LAGA · March 15, 2008

I would like to get opinions on what is best for the life of the trans. That is my main concern.

ridnlow · March 15, 2008

Contact these guys..

http://finishlinetrans.com/contact/index.htm

VMax2007 · March 16, 2008

I am a member at ls1truck and Vince from FLT is also a poster there. I asked for his opinion on my 4L70E after the Nelson tune. He told me to leave it alone (no Vette servos or shift kits) until my warranty expires. He said "Let GM fix it until the warranty runs out, after that, then mod it how you want to". I plan to do just that. In 4 yrs (when my PT warranty expires), I will be contacting FLT and I will build it up then.

Here is our PM transcipt:

Me:

Vince,

I have heard your the guy who could answer my ???'s.

I have a 2007 NNBS GMC Sierra CC VMax 6.0 with the 4L70E tranny and 3.73 rear end. I have recently installed a Nelson Perf Tune, 91 octane. Allen removed 100% of my TM and all of GM's Abuse Mode Nannies. My question is should I be ok with the stock 4L70E tranny or should I be considering upgrading it? What would you recommend? Also, please keep in mind I have a set of stock ECM/TCM modules for warranty purposes and would obviously prefer to maintain my warranty. But after my warranty expires I would be willing to do whatever is necessary to make this thing bulletproof.

Your thoughts and honest opinions are appreciated. I have heard FLT is the way to go with built/rebuilt trannys. Right now I am thinking just leave it alone and if it blows up, make GM fix it, and if it makes it past warranty, either build/rebuild it or upgrade it with servos, shift kit or whatever.

Thanks!

Jeff

Vince:

At this point your truck is covered by the warrenty so let the dealer buy you a trans if it blows up. After wards you know who to contact. Take care. Vince

Me:

Vince,

Thanks for the input. That is what I figured.

On a side note, what is your impression/opinion on the 4L70E as compared to the 4L60E and the 4L80E? I have heard the 4L60E is weak in stock form and the 4L80E is fairly bulletproof. Is the 4L70E closer in strength/longevity to the 4L80E or 4L60E?

Thanks!

Jeff

Vince:

The 70 is just another version of the 60/65 if that makes sense. The 80 is a much stronger trans but the conversion can be costly and also some loose power running this combination.