99_TRANS_AM_LS1

I just got my car running with a fresh rebuild engine. I took it out for a drive. With throtle wide open shifts 1st to 2nd nice n firm but it wont shift into third n the engine just revs up.

99_TRANS_AM_LS1

What could it be? Any ideas?

mrvedit

Its a common problem with the 4L60E - the 3-4 clutch is worn out and your trans needs a rebuild. There are many threads on this. Here are a few recent ones:

https://ls1tech.com/forums/automatic...ips-3-4-a.html
https://ls1tech.com/forums/automatic...4l60e-kit.html
https://ls1tech.com/forums/automatic...-problems.html

99_TRANS_AM_LS1

It goes thru all gears when im not putting the pedal to the floor but when i do from a dead stop it does rev and wont shift into third. i think it may be the tune, the engine got rebuild it got bore and new ultra gold rocker arms also the tranny got a new pump, so i think the tune that currently has need s to be retuned to the new aspects of the engine, you think it maight be it?

jakemussman

iTrader: (1)

+1 for 3-4 clutches
The tune could account for a no shift. It would not account for neutraling out.
there is more holding power required from the friction discs when you are out romping on it in comparison to lightly accelerating from a dead stop. They may just be beginning to go out.
Hate to say it but it sounds like you have a rebuild in your very near future.

99_TRANS_AM_LS1

damn! hate to hear that, a friend of mine had told me something similar, he said that with in 1year of putting in my new engine i would need a new tranny. at least i know what to expect if it does fail, i think ia start looking at some rebuilding shops, there is one called calspeed performance in bakersfield ca, they can get me a stage 5 trans using my shell for around $1800 installed. i might give them a call.
thanks the help.

mrvedit

If you are hitting the rev limiter in 2nd gear (before the shift), then that indicates a tune problem.
However, if there is a shift and it then revs easily without much acceleration, it is the 3-4 clutch.
You could accelerate at 1/2 throttle until it shifts into 3rd and then go WOT to see if the clutches hold.

EDIT: There is a similar thread now too: https://ls1tech.com/forums/automatic...shift-wot.html

99_TRANS_AM_LS1

that is exactly what is goin on, it hits the rev limiter in 2nd and it wont shift. i hope is the tune, i am gonna take it to get tuned maybe next week.
thanks for all the help. i ll keep you guys posted after the tune n see if that fixes the problem.

mrvedit

OK, lets hope it is just the tune.
Sorry if I scared you, but your "just revs up" confused me.