i have an 86 ss with a 350 and the same transmission since i got the car 4 years ago, its been rebuilt maybe 2 years ago. its now making a "rattling" noise expecially when i acclerate, the shifting and time is perfect, its not slipping or anything and dosent seem to be affecting my performance. i drove to ihop this morning, ate, came back out and when i started the car it made a lound CLINKING!! sound? ill take it to my transmission guy but hes on vaca at the moment and i dont trust anyone else. lol

 

The first thing I would do, would be change the tranny fluid and see if that make any difference. The would and could be the quickest fix.

 

Well found the problem, the loud clinking noise was one of my bolts to my flywheel breaking and flying out lol, and to add on to the rattling noise the other 2 bolts were very loose.