[Steeveedee]

Originally Posted by HO455

I would put it up jack stands and get a trusted helper to run the truck on the stands while I got underneath and tried to locate the source of the noise. It could be a rear axle bearing gone south, or like the one in my Burban where the housing was full of pieces of my disintegrating carrier.
Good luck.

Note- those jack stands should be under the axle housing so that the driveshaft is centered on the bearing. Ask me how I know. I learned that one in about 1975.