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I have had my vette servos for about a week and this morning I noticed it was not shifting like it had previously. Also I had some of my buddies in Auto. Mech. ride with me who did when I first installed them to make sure I just wasn't getting used to it and they also noticed it wasn't like it first was. Does anybody know what would cause this? All coment appreciated!!
The ECU will adapt to the changes youve made in your transmission. Have you installed your Nelson tune yet?
Yes, Nelson tune has been in for over two months. Servos, 1 week.
Its simply a function of the ECU adapting to the servos. Dont let it fool you, there still performing like they should be, its just smoothed itself out.
Will a retune get my shiftfirmness back and keep it there?
Eh, I would leave it alone. Do not increase tranny shift pressures. Just remove torque management.
So now with the servos will the tranny beable to hold up to no TM, and how much does Nelson leave in there for a stock truck?
Mine have both done the same. It's called TAP (Transmission Adaptive Pressure). You can constantly reset the TAPs with a scanner or have the pressures modified in the tune...or removed most/all TM. You the only way to keep them firm is to up the pressures. Even removing TM won't keep the PCM from pulling pressure to get the shift times ''correct'' via TAP.
remove the pcm controlled transmission pressure control solenoid on the transmission and replace it with a Transgo vacuum pressure control module and your shifts will be consistant. :thumb: You vary the shift firmness by lengthening or shortening the little push rod inside the Transgo kit. :rock: Only bad thing is that you have to drop the trans pan to make mods.
If all else fails I had the same issue after I rebuilt and installed a shiftkit in my 4l60e I shifted nice and firm all gears but especially 1-2 upshift, then one day that shift got really soft, softer than the others, I removed the transpan and the 1-2 accumulator piston housing, the one held to the trans inner case by three bolts, and found that the plastic piston cracked and was letting pressure leak through it, I replaced it and refilled the trans and drove it, and it took care of my problem, so this might be something to think about...
Yep and the 1-2 accumulator piston is plastic stock. It can be replaced with a metal one and a different spring that allows a firmer 1-2.