2xLS1

iTrader: (25)

Would like to hear from Vince@FLT and Performabuilt on this. I've always heard that WOT 3-4 shifts on 4L60s will kill them pretty fast. What is your opinion on this on both stock and built transmissions?

performabuilt

iTrader: (25)

Well diferent people have different veiws the weak link of a full throttle shift into fourth isnt actually the application of the band but the fact that power is still being transfered through the 3-4 clutch ,This is where additional clutch sets or sets such as the z pack shine since they give that extra holding , And in many ways the 3-4 shift is less stressfull on them because they are allready applied and just transfering power and not having to apply during the shift as with the 2-3 shift ,
Personally as long as you have some upgraded clutch pack in the 3-4 set and arent spraying through the 3-4 shift.and the limited opuritunities you would actually be doing that since unless you are geared incredibly low in the rear , I wouldnt see it as a problem , but man if your asking this question you must like traveling alot faster than I care to go unless your geared 456 or something .
Now with the stock tranny with a stock 3-4 set i would say no ,

FLT

iTrader: (1)

I think it is ok for a full throttle 3-4 if you have a good band in your transmission. Also a sonnax 4th gear servo is a good idea for full throttle 3-4 shifts for added holding power. I think what happens in most cases is the band is partially burnt or not adjusted properly and it will slip under these driving conditions. Vince

2xLS1

iTrader: (25)

Thanks guys. I see where GM programs the 3-4 WOT shift mph at an unreachable level making you have to lift to shift. I don't worry about in my cars, but sometimes owners of cars I edit question why they have to lift to do a WOT 3-4. I've always been reluctant to set a 3-4 shift point that is reachable at WOT for fear of hurting the transmission.