Clunk in reverse?

[Murray the Cop]

After towing my 5er for any period of time I eperience two clunks ,one right after the other, just after shifting into reverse and starting to back up. Any ideas? 2500 DA/Ali 4x4. Thanks

[HowieE]

I wouldn't drive it any more than necessary, none would be better, until someone looks at the U joints and rear bearings. If it is in the rear you don't want to move metal around in there and do any extra damage.

[ropinfool]

are you still hooked to the trailer??? Where is the noise coming from? John