So whenever I slow down to about 15mph I'll get this little clunk coming from the rear I believe. And sometimes when I'm stopped and start going it'll happen. When It happens when I start going if I go slow and stop and start I'll happen as soon as the car starts moving. It's not always constant otherwise.

I checked the U-Joints, took the drive shaft out, cleaned them up and tightened them back up. It actually stopped for a while but now It's starting to happen again.

Any ideas of what the problem could be?

 

Anything loose under the back? Spare tire, exhaust, shock, evap canister, bumper, hitch, roof rack etc.