Ok..Here goes my attempt to explain..Car makes a noise when changing gears from 2-3rd(automatic 700r4)...This noise has been here with old and new trans rebuild,has been here with old and new rear end(from 273 to 342), has been here with old control arms(stock to Hotchkis),and same with new panhard(from stock to Hotchkis)..The noise is more prominent when in "drive" versus Overdrive..more prominent at low speed shifts,i.e not stomping on it..The noise is a clunk,low end like a rubber mallet..oh, and a new trans crossmember switched from stock....noise seems from the rear,my guess is axle ?..but I do not have any more clues..Looking for someone who may have experienced something similar, and the fix it may be..Thanks alot...If I left anything out let me know...

 

possibly a torque arm bushing?...even tho' it looked ok?

 

Maybe U-joints?