harsh shift = valves sticking????

Hi - I've been sitting here for an hour reading through this forum - you guys sound like you know quite a bit about engines. Anyway - my 2001 Buick Regal started to 'jump' or 'cough' when making gear shifts (I've got about 56,000 miles on it). It seems that the car would need to warm up for a while before it would start doing this. I took it to Mr. Mechanic, who did a full transmission flush. Well - as you probably figured out, it still jumps. I returned to Mr. Mechanic who then went with me for a nice ride to see what we could find. After 'jumping' through all the gears, he says "the valves are sticking"....ok, that's fine, but I'm a little leary of dishing out $500 or so bucks for a valve job if that's not what's making me 'jump'. After reading some other posts here, it seems like it could be several things....any advice? Comments? Experience? From some of the posts I could find, it looks like it's not a problem that's isolated to just my car. Thanx in advance for helping.

Welcome to AF, tough to understand what " jumping" means, non auto term here. Second what valves, engine, trans.? A full scan should be done to look at trans solenoid functions and codes. If this is a trans issue, the press. ctr. solenoid can cause this but proper diagnosis is in order you may need a back up diagnosis from your " Mr. Mechanic".