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The noise could be coming from the differential snubber bushings that are between the rear bracket and frame. There should be no moving parts in the rear when the car is idling, maybe an exhaust pipe hitting the frame?
Gary
The clunk noise is probably your front diff bushing, cheap to buy the part, pain to change it. If the bushing is good I would check the u-joints next. As for the noise while it's in park I'll second Gary, shouldn't be any moving parts. See if something is vibrating on another part.