Mystery sound - U-joint, differential???

My wife's CRD 06 started making an intermittent clicking, tapping sound (like a stone in a wheel)coming from right rear tire area. Sound speeds up, slows down with pace of vehicle comes and goes mostly when cold. Lasts for a 30 sec. Placing vehicle in neutral (automatic), speeding up engine, or braking does not make sound go away, putting it in 4 wheel mode does not affect it. Any ideas??

Revray, hard to say with without being there but I might suggest ,if possible, to elevate the rear end with jack stands and put it in gear so you can get a better grip on the matter, maybe something in the caliper?

Betting on U-joint.

It is with embarrassment as a diy - to admit that it was the emergency brake shoe pads. I have worked on multiply cars, vans, but I had no idea that the emergency shoes where inside the rotors. I had previously taken the right rear wheel off, checked the brakes, but Sat. I took your advice elevated the rear of the jeep, crawled underneath, - noise came from the right rear tire. Took off the rotors out of frustration, and the emergency shoe brake pads fell out in fragmented pieces. Rickshaw thanks you were in the right zone. Thx

Bravo!