97 Sable Vibration/shudder problem

I have a 97 sable, while driving and startingat about 30 mph i get a quick vibration/shudder right after the change in gears. then it stops just as fast if i take my foot off of pedal or accelerate, it also stops asap. it also happens thru out driving ranges at all speeds i checked fluid which is full and still pink and clear no burnt smell no other shifting issues. anybody outthere with any thoughts on this problem i would greatly appreciate your help!! thanks in advance! K