...That's for LS4 cars? Because last time I took the car in, I asked the service manager to look up TSBs AND road test the car. They swore it was 100% normal.

 

No, but I googled TSB's for 08 impalas.

 

Well, the car behaved perfectly on the way to the dealer and no surprise, it didn't do it when the dealer test drove it. So, they want me to bring it in asap when the car acts up so i can take them for a ride. How did I know this was going to happen. On the bright side, they did not charge me a diagnostic fee. Oh, this is the link to the TSB i was looking at http://ww2.justanswer.com/uploads/Sp...915_094569.pdf

 

Car has been acting fine, if I don't get anywhere before winter then I think I'll put in a transgo shift kit in and I already softened my wife up for HPTuner to up the line pressure of the tranny.

 

put in a transgo shift kit

 

Does this 1-2 shift problem feel like the trans isn't in a gear and then it sort of violently shifts into second?

 

Have them check the front motor mount.

I had the same symptoms. My front motor mount was shot to ****. I cant be sure if that was really th problem though because they also gave me a rebuild. Either way, the tech I drove with felt the issue I was stating (same as you) and could tell right off the bat something was wrong.

 

No it has never slammed into gear. just while going from 1-2 the car shakes a bit. Funny part is it hasn't done it but once since i brought it to the dealer. I will check the motor mount tomorrow, thanks for the heads up.

 

I think you mean clutch pack.

 

Have you checked the fluid level and condition? Also keep in mind at 50k the fluid/ filter should be changed if you are not running it on the highway very much.

 

I changed the fluid and filter at around 38kmi and it was dark but not burnt. The fluid level is good and the color is darker but still ok. I filled it with Amsoil synthetic and that took care of a delayed 1-2 shift at the time when the tranny was cold and it was cold outside ( under 32F). I'm figuring on changing the fluid every 30kmi on this thing.