So I have a bone stock 99 Trans Am.. the car has 114k currently on it. the issue Im having is sometimes when I hit it at on the freeway it car seems not able to shift into 4th. it just revs to redline. After doing a bit of reading it sounds like the synchros go bad and this is a common issue. what do you guys think?

 

What kind of trans?

 

whatever comes standard in that year

 

Auto or manual? The reason I ask is because automatics don’t have synchronizers.

 

Auto trans, also thanks for the info

 

First, welcome to LS1TECK

It could be that your 2-4 band has worn to where it doesn’t hold any more. In most cases the band will act up in 2nd before 4th.

See post #2 from mrvedit in this thread
https://ls1tech.com/forums/automatic...cond-gear.html