firebirdlover

If I granny the clutch and not hammer it...it will not do it. But if I get on it a little from a stop I hear a popping / clunking sound in the rear. Dont know if its a bushing or u joint or the actual rearend. Any suggestions of how I can diagnose it? Car has 75k and I changed the diff fluid already but symptoms are still there.

Thanks for the help.