2004 XJR. 2 problems with noise in the same passenger side rear wheel area. I'm assuming both noises are related. About 10% of the time when I back out of the driveway and turn the wheels and go forward,...sometimes I hear a thump at the rear passenger side wheel. I took everything out of the trunk and still had the occasional thump. Even less frequent than the thump, (once I shift and move forward), I have heard / felt a rub that "rubs" the wheel with every wheel turn for the next 30-75 feet (varies) and then it seems to go away and fix itself.

The second noise is noticed at higher speeds. At usually between 55-75 mph I will hear a relatively strong vibration from the same wheel that lasts about 2 seconds. I drive the car and don't hear this vibration most of the time, but at 30,40 or 50 miles it might happen again at higher speeds. It sounds mostly like the wheel traveled over a warning strip or grooves in the road. I have heard people use the term wash boarding. You might have to drive the car 20 or 30 miles before it happens again. The dealer has a hard time making the noise happen. They put the scope on it, but still does not know what it is. Is something hanging up? And in the case of the vibration, it does not seem to matter if I accelerate or coast. Differential? U-joints? Rotor? Any ideas would be greatly appreciated. Thank you!!