8 1/4 axle inspection.

in case it's just a wheel bearing, I think I'd pull the axle shafts, first, and examine the axle shafts' wear surfaces, and the wheel bearing rollers for flaking, nicks, spalling, etc. It may or may not be 'your' issue, but it'll need to be addressed anyway if there is a problem with those parts. just my 2cents.
good luck.