I've noticed clunking on my rear too. feels like play in either diff/drive shaft/ axle? Car is being prepped for real man skids
Check the differential backlash by rotating the halfshafts and tail shaft, with the wheels stationary. If there's a fair amount of movement then it needs to be adjusted, meaning the diff has to come out and the tinkering with shims or whatever begins. Mine has a lot of play at the momemet, and the clunking is really annoying. Tap the throttle and it feels like there's a steel ball bouncing around down there. yeah that's pretty much what mine has been doing man. wheels have a bit of play when jacked up at the rear too. could probably use a shim I guess.