May not be abnormal - when you are spinning one tire the spider gears in the diff are rotating which make a clicky sound like that. Do you have abnormal noise at driving speed? Any other symptoms?
It does that when you spin either wheel? And the pinion/driveshaft is not turning in the video, is that correct?
I'm thinking spider gear more than a bearing. Have somebody stick their ear on the pumpkin while you spin the wheel, or just yank the diff and have a look. You'll probably have some pretty shinies in the gear oil.
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'My needle always settles between west and southwest. The future lies that way to me, and the earth seems more unexhausted and richer on that side.' - Thoreau, sort of.
It could be the bearings but usually when they go you'll also blow the axle seals and it leaks all over the place. Take the rear rotor off (the drum cover) and if it's wet and goopey then you found the culprit. If not, I second draining the oil. Worse case it's fine any you just pump it back in there. Make sure you take out the fill bolt before the drain bolt so you know you can get it back in!
I would say check the gear oil now. It sounds to me like you have lost your oil and so the gears are chattering. A bearing would have a cyclical pattern that has the same frequency as your tire spinning. That is making many cycles per wheel rotation.
__________________ 2000 SR5 3.4L V6 Automatic 4x4, e-locker, 175k Miles, Rust Imp. Jade Mica with Oak Leather Interior, Field Monitor Unit - B&M Tranny Cooler - SG2 - New (to me) rear axle assembly - Goodyear Duratrac 265/75-16 - 1.8" Ironman Front Lift, OME 906/Procomp 9000 Shocks