Charlie; If your car is a Z-51, see post 136 in the thread below. It might cover what you are hearing. If your car is not a Z-51 you might want to get the hypoid grease / lube level checked in rear diff. What is the manufacturing date of your car?Thanks, guys. But we seemed to have missed the essence of my question. In the title and in the message, I mentioned specifically, the REAR of the Vette and not the front end. The clunk I hear and feel is reminiscent of the old positraction days when either the wrong limited slip differential fluid was used, or the unit needed to be "broken in". "Younger" enthusiasts may not even be familiar with this particular problem. Thanks.