Thanks for the tips. Naturally, I replaced the sway bar links just a couple of months ago, so that was a few bucks wasted. Ah well....

My '05 4.4l AWD has been FWS for a while now (can't spin the rears on ice, when up on jacks the prop shaft spins but the rear axles never do)...local independent was able to communicate with the DEM and got no codes, and diagnosed it as a mechanical failure in the rear differential. Looks to me like...