hey guys give me some ideas here. my wifes 94 GMC sanoma is making a weird type harmonic sound from some where near the rear end. it's a matalic type humming kind like humming into a hollow metal tube at a high pitch. it will make this noise unsder accleration from first gear into second gear. and the quit. i don't think it's the rear end cause it qoes away but i have been know to be wrong (just ask my wife).i wanna think it has something to do with the drive shaft cause of the sound, but it think the drive shaft is just the object the is transmitting the sound form the rear end or the tranny /forums/images/graemlins/dunno.gif any ideas?