Well my saga continues. I do not think it is the differential, but is not totally ruled out. The thump, (now that I have payed special attention to it), seems to be more like a click or a tick but a bit more deep and harsh in sound. I hung my head out the window and it seems to be coming from the differential area. However, I had the wheel up, and carefully spun the shaft and did not feel anything unusual. If there was a chipped tooth, would it need more torque than my hands spinning the shaft provided to surface? The joints seem to be fine, all is tight and the problem is not a vibration, it is a clunky click. I also turned the driveshaft back and forth and a seemingly similar sound came from the transfer case. When driving, I put it back and forth from 2wd-4wd and no difference in sound or feel. Is it possible that the output bearing to the rear driveshaft would make this noise? Could it still be the diff? The rear bearings were replaced 5,000 miles ago, guess it could still be this. Any more troubleshooting methods, thoughts, or anything would be great. P.S. I can feel the tick/click on the transfer case shifter, not violent, but can be felt.