92 Bonneville SE with 3.8 V6 and automatic, 178K miles... When I am in Park and I rev the engine, as it decelerates I hear ths loud banging or clunking noise from underneath the right side of the engine (open the hood, and it sounds like it'* from the tranny). You can actually feel it inside the car, and also feel the vibration iwhen you put your hand on the front tires. When the engine finally returns to idle, the noise gradually goes away. Sounds like something flopping around inside the engine or tranny. When in neutral, I can get the same noise only slightly muffled. It is nt heard when any gear is engaged, and I hear nothing while driving. Tranny feels OK, shifts OK and the car runs fine otherwise at all speeds. Took it to Aamco and the guy showed me a drice chain from a disassembled tranny. He said it might be the drive chain loosened and it "slapping" the inside of the tranny. Anyone had this problem and what is the cure... a new tranny? BTW I am trying to sell this car ($1400 in Florida) and this is making it dificult to sell!