My rear thunks on acceleration or just going from reverse to forward. I don't drive this car roughly either.

I have replaced all the bushings in the car with poly. I have new u-joints. Have taken the half shafts apart and cleaned and re-lubed the splines etc. I have a new differential mount. New shocks/springs. Every thing is new and tight except the differential itself and the strap that goes over the top. I think the Z just clunks. Good luck.

My car did the same thing. When I would get on the gas it would clunk. If I would let off the gas it would clunk again. I had replaced all my rubber in the back and used poly where available. Upon closer inspection I noticed that the nut on one side of the mustache bar had come loose. I replaced the nut and the clunk is gone. Sounds like you have the same problem. Check it out. Your car should not clunk.

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