Originally Posted by RamTech
If you have a whine and the oil level is correct, chances are that you have a bearing that's bad. Lack of the LSD additive would not have caused this problem. If you have the bearings replaced before any ring and pinion damage can occur, it shouldn't cost as much.
depending on the bearing its not that difficult to change, if you are the slightest bit mechanically inclined (and have a good service manual I.E. Haynes). I have rebuilt a one ton rear end. the hardest part was getting the broken bolts out the axle cover.