Droning noise in the drive train?

[MTGunner]

There is a droning/whining noise somewhere in the drivetrain of my 2000 R50 4x4. I checked the rear diff for fluid and all is well. The rear tires show no different wear from other tires. I will check “U” joints tomorrow. Will also check rear axle bearings by jacking rear end and placing on jack stands. Droning/whining noise diminishes with higher speed. But, am concerned. What think you all? Thanks for the input. MTG

[MTGunner]

OK all, this far I have replacedfront wheel bearings. Cleaned up a bad brake job as the pads were no being allowed to float on the right front wheel, very tight and not installed correctly. Checked the universal joints to find no fault. I had a good friend ride in the back seat while I was driving on a fairly smooth road an$his opinion is that the rear diff gears are a small bit loose. He said, and I quote, “it will probably only last another 100,000 miles in this condition. Well, I will drain the rear pumpkin and look for debris. If nothing significant I will refill with synthetic diff lubricant and move on. 

Front end steers great, brakes work great, rear end noise is minimal. NEXT!

Edited February 3, 2019 by MTGunner

[MTGunner]

Dumped the diff fluid yesterday and drained for an hour. The drain plug magnet had but a small amount of black debris, looked like black mud, no metal chunks. Refilled with Lucas 75-90 synthetic diff lubricant. The droning noise has dimished to a point of nonexistence at this point. At this point I will monitor for other noises. Tough being a person that hates noises, rattles, squeaks and the plethora of annoying little things that come with a used car. 

Sure do like my R50! MTG

Edited February 6, 2019 by MTGunner