I've got a thumping noise coming from my rearend. Is that the universals? It's a 1988 RX7 Convertible, 5-speed.

 

broken differential mount

 

I'll second that it is most likely a broken diff mount. When you give it gas does it go thump on the bottom of the floor?

 

yeah its an easy fix though. theres a bolt that goes in horizontally, holding your rear end in place, and all you did was shear the bolt. make sure you jack up the car from the sides and not from the back because your rear end isnt stable.