I have spent the past two weeks trying to find a trans to swap in my 2003 chrysler sebring 2.4L. After 2! failed attempts from pull a part I bought one off an average joe this morning. Third times a charm, the transmission I believe came out of an 02 Dodge Stratus. Heres my problem all gears there is a hard up shift especially 1st to 2nd not as bad on the downshift but still noticeable. So my question is does anyone think a re-flash from a dealer would fix this problem being that it came from a different model? Any ideas would be greatly appreciated, Thank You.

 

Dealer will probably want to run a "Quick learn" procedure with his magic box (DRB III) scan tool. It's a standard procedure after any major transmission work. It might help smooth out the shifts.
Alternatively, you could live with the rough shifting until the transmission computer learns the idiosyncracies of your new gearbox and smooths out the shifts itself. It's designed to do that, you know.