[Excaliber]

Well it WAS the wheel bearing clearance. I took it all apart and the bearings and races looked good. The races fit tight in the hub etc. There was considerable play in that the wheel bearings were "loose" (not drawn up tight) against the "race".

Unlike a front wheel bearing where you simply tighten the nut to adjust the bearing clearance on a Jag IRS you use different thickness "adjustment spacers" and tighten up the axle nut to a couple of hundred pounds of torque. That carefully chosen "spacer" stops the bearings from being drawn in to tight against the "race". Wrong size "spacer" and the bearings are to tight or to loose.

Spacer, bearings, hub, axle and u-joints are all fine! The freakin' axle nut was under torqued and the bearings were not correctly compressed into the race!

I'm torquing them to 200 ft lbs after reassembly. I "bench tested" 200 ft lbs and the clearance was good!