Hello folks, I'm back! I finally had some time to work on the Jeep, drained the t-case last night, let it drain overnight and this morning.
Did some other tinkering then refilled the t-case with 30 wt non detergent and friction additive/modifier as was suggested. Went for a drive, tried several tight turns and hard accelerations and yes, the noise is gone!
Thanks to all who replied with suggestions and info.