Rear end noise

I recently noticed a popping noise from the rear of the jeep at low speeds, especially when turning. Now I hear a pulsating, rubbing noise at highway speeds. I had a friend help me check it and this is what we found...

No play in the drive shaft, but one of the U-joint caps is cleaner than the rest, almost shiny.

The driver's rear tire jerks every time the popping noise is heard while turning at slow speed.

Any thoughts or ideas before I pull the axles and bearings?

Inspect the rear brakes for worn or broken parts. Open the diff cover and Inspect the Gears and Carrier. If you have a Limited Slip, it will make noises if you don't use the special Limited Slip additive lubricant.

Thanks for the reply. I forgot to include one thing in the OP. The driver's side sits about an inch lower than the passenger's side. Air pressure is equal on both rear tires.

Tim_Mn has given you good advice.

Worry about the height difference after you have fixed the problem--I doubt seriously if it is related.

Thank you for your assistance. I'll be doing those things you suggested.