1995 GMC Sierra noise

A rattling or banging sound from that area is usually caused by a cracked flex plate. To find that you can often turn the engine by hand at the vibration damper, and the ring gear on the flex plate won't turn as much. Put a chalk mark on the ring gear teeth and the transmission case, then rotate the vibration damper a tiny amount and see if the chalk marks move the same amount. If you see a definite delay or difference, suspect the flex plate. Sometimes the broken parts get wedged together and you won't see that difference. Then you have no choice but to take it apart to inspect it. The breaks occur right around the six mounting bolts where it bolts to the crankshaft.