You mention grease vs oil bath, so wouldn’t the bearings be serviceable? I think of a sealed bearing like a hub bearing that are on modern cars. And they are not serviceable. I thought the older DRVs hubs were an oil bath set up? I thought in 2015-16 they switched to a greaseable bearing style hub. Atleast on the Moryde suspension system.
2015 Ram 3500 Regular Cab DRW CTD Asian trans 410 rear