tranny slips when upshifting

[Kewltalon]

Hello
I am new to the automatic tranny scene. I just rebuilt the motor and installed it in a 92 6 bolt awd talon.The car was sitting for a year and a half with the head off and i bought it. While doing a few runs to seat the rings, I noticed the tranny slips out of gear when up shifting, especially in 3rd to 4th. The fluid levels are good and I put in a new fliter and fluid. Any thoughts? Thanks.

 

[doug]

Sounds like one or more of the clutch packs are starting to go. Hopefully it's only the end clutch, which is easy to replace. If it's one of the front clutch packs, that's not so good. I ended up having to get a completely new tranny when mine started doing that.