Another place to check Are the rear hangers for the muffler. When my mechanic installed my diff bushings he had to remove the muffler for clearance and didn't put all the bolts back on the hangers (only 1 per side) and the hangers worked itself loose due to movements in the exhaust system, this is where I discovered where my "clunk" had been coming from. I originally thought it was my rear sway bars endlinks had gone bad and bought new end links to replace it but it was the damn muffler hangers!
