I have a 67 firebird 400 with a 3.08 posi; put new axles and bearings in it about 5 years ago because one of the axle seals was leaking. I was told the axles needed replaced at the time so they are new as well. Just some background there. I have had the car for 8 years and I believe I have always heard an occasional clunk from the rear, not a loud one, but I can hear it. One shop I use thinks that means the rear needs to be rebuilt, does that mean the rear needs rebuilt?