i have a 97 z28 a4 and the transmission has been acting funny....i recently just did a complete tuneup on the engine and also drained the trans and rear end...i installed a new filter screen and pan on trans as to previous owner using a jack on it to raise the car...my problem is when the car is cold the transmission slips in od...but not in any other gear. but once the car warms up the slip goes away. i didnt have this problem before the work...im confused as to what it could be. any thoughts?? i also used amsoil atf.