i think you jinxed me cause now i have that same noise, i tightened my transmission bolts, which were a bit loose, but my exhaust was loose. which was causing most of that noise. those no gasket type metal crimps had some loose. i also checked my transfer case oil and it was a bit low. now that i topped it off the sound has just about gone away. but remember the tranny is 25 years old, thats what i keep telling myself anyway. these trucks are almost bulletproof...where can you find a main drive train that is 25 years old, that has taken a beating and is still ticking besides a yota? no where!