Folks,

Thanks again for your expertise!

I tried an interesting experiment of couple of weeks back to determine the source of vibration... but with no success. First was Larry's suggestion of offsetting the center bearing support, no-effect. Then I jacked the car up and then put it down on jack stands under the rear shock mounts. My theory was it would keep the axle half-shaft orientation closest to driving as opposed to having them droop downward.

The family was away so I had to try and look for the vibration alone. I first tested taking the car up to 50-55 on the jack stands. It had the vibration appear, but no sense of un-steadiness on the jack stands while running. I did have secondary jackstands and spare wheels under the body as well for backup.

Being alone I used a my camcorder to record front and rear driveshaft and each axle. Curiously there was no discernable vibration to be seen. It could be felt. The camera was about 3-4 feet away but I didn't see any vibration shown in any component. At over 260K now I expect it is worth trying center bearing and flex disks anyway.

I hope to have an update in a week or so.

Chuck