Rear End Clunk

[Robert M. Shydo Jr.]

Been getting a clunk in the rear of the 5kqt on transition from coasting
to power and vice versa since shortly after I got the car.  Thought it
would be a loose rear subframe bushing, but after crawling under the car
and playing with stuff that doesn't seem to be the case.  In gear with the
parking brake engaged, the shaft will turn about 15 degrees then stop.
U-joints are fine.  When driving hard, the sounds almost is like hitting
an aluminum baseball bat with a rock.  Thinking it must be the rear diff?

Rob