[PaulProe]

Larry,
I converted my car from the Poly bushings that came with the IRS (Hurricane) to the spherical bushing mod that Dave Borden/Whitby supplies.

The sound is a "rotating" sound. I fought the poly bushings to get rid of the squeaking sound (and won) but this sounds like something rubbing.

My next guess is to try a bottle of Ford friction modifier. I switched to Lucas gearlube which is supposed to have modifier in it.

The sound seems to be worse in a hard right turn than in a left turn or when the suspension loads/unloads to its extremes. Maybe it is the differential clutches.

I noticed the tightness of the halfshafts and was chasing down the customer support number of the DriveShaft Shop but haven't called them yet. They seemed like they were binding slightly but I can't imagine how that could be.

Paul