Rear end hot rim to rim...

So hot you can't hold hand on rims, housing or center case. It started howling on a 15 min trip. Pulled plug on diff and fluid was full enough to be dripping out. Brakes are wilwood disk and they are not locked up or dragging. Any ideas why so hot, sounds like noise from bearings maybe at axle ends, but I could be wrong.

And what rear end are we working on?