Mmm...well...the link seems pretty solid.
My father-in-law and I took the cover off the rear diff. No missing teeth. With one wheel still solidly on the ground, the other in the air, we turned the suspended wheel slowly. All the spider gears were fine, the ring gear appeared happy. I
did notice, however, that there was one point in the (free) wheel's rotation where it seemed to bind more than any other point. I wouldn't expect that for gears that have meshed for the past 119,000 miles. It wasn't severe but it was noticeable. I siliconed the cover, put it back on, put Mobil synthetic gear lube 75w-90.
(Odd thing - the capacity of the rear diff, according to websites I've visited, is 2.19 qts...aside from some clumsy spillage on my part, I got most of 3 qts. in it and it didn't overflow out the fill hole.)
It's still making the sharp clunking noise as you start from a dead stop and the "whirring"/rumbling on deceleration in gear.
We took it to the local Dodge/Chrysler/Jeep dealer and asked their off-road Jeep geek/salesman to take it for a spin. He was 99% certain something in the rear diff was sorely out of whack until we told him we took the cover off, didn't find any missing teeth in several rotations of the wheel and refilled it. That's when he said there might be some kind of "crack in the something something case". Sorry, I kind of glazed over when he told us the name of the case. During his test drive, he said he thought the rear end "hopped up in the air". Could the problem be something that would only be apparent when motor torque is put to the rear end?
The latest game plan (mind, my wife has had this problem for almost a month so she's going a little crazy without her beloved Jeep soooo...we're trying to keep moving) is for a buddy from church who used to own his own metal fabrication shop and still does mechanic work on the side, to take a closer look at it. Assuming the rear end really is out, we'll pull an entire rear axle from a junkyard and put that in. N-O-T looking forward to that but, as he reminded me, there's a whole bunch of labor with shims and all that happy stuff, putting new guts in the diff.
However, I really value the experience and know-how of longtime Jeep fans.
[b]ANYTHING[/b] you, or anyone else reading this, will be thoughtfully considered! Please feel free to contribute! Heck, maybe you know the name of the case he was talking about. Yes...I will pass out if it's the transfer case - please break it to me gently!