Even when the noise is only producable on one side of the differential?? I ill drain and examine soon....

 

I dare to say the issue may be resolved. I chnged the differetial fluid with some Royal Purple Gear lube. There was evidence of very fine metal shavings. There was also some metal sludge stuck to the magnetic drain plug. I drained, filled with on quart and drained again to remove any particulate and refilled to spec with Royal Purple 75/90. All low speed indications are gone, no metal on metal, no tapping or clicking. I went to a large dirt parking lot and tried to get the front end to "groan" at speed as it used to and it would not do that. Then I took it out on the freeway an dwas doing up to 90 mph with no noticable vibration as there was befroe over 75 mph. While I beleive there was and still may be a small gear issue, having the correct weight and viscosity fluid in the case is definitely helping. I guess we'll see in a few thousand miles how often I have to change that fluid. If I get more buildup or not.