Steve,

Thanks for the comments. I am hoping to get time this weekend with a few friends in town to get it up in the air and listen / shake some things around myself.

I guess the first step is to watch and listen. I know the dynamics will be different without any load on the car. Also will the wheels / axles dropped down and therefore at different angles than usual... this may be masking an issue. I have never run a car in the air before at speed, and not one with independent rear suspension. I'll remove the driveshaft shield and check the bushings / driveshaft as well. Two pretty good shops have done this and not recommended driveshaft or the center bearing so far, but worth looking myself now. It may well be the issue Larry discovered with wear in a particular part of the u-joint and shimming it fixes that.

Can I remove the axles and run the driveline (up in the air) to see if it still vibrates? Anything it would hurt? It may be worth a first try at switching the axles - are they interchangeable? Larry's shim recommendation may be an easy try as well.

The primary place I have taken my car is PAS Automotive on W. Palmer (near the Panther's Stadium). Mike is the mgr and Kurt is the excellent mechanic. Kurt was in the hospital earlier this week. (Kurt had briefly looked at the vibration 6 months ago and did not see a clear diagnosis either). He is their only state inspector so I was looking to go somewhere else this month.

Based on a recommendation from this forum I went to MBV European Ltd. They are on Old Pineville Rd between Tyvola and Woodlawn (closer to Tyvola on the I-77 side). They looked and looked at the vibration issue and did not charge a diagnosis fee. Seemed to be an ok shop and had many Mercedes, Bmw's, and Volvo's there. Customer interactions with the Mgr were friendly while I waited... more good signs.

Chuck