Rear End Troubles

Has anyone had, or heard of anyone having rear end problems with their Trooper. I have a 2001, and have had a clunking noise when the vehicle downshifts to a stop. It seemed liked driveline U-joint issues, but I brought it to my mechanic, and he claims it has alot of slop in the ring & pinion gears in the rear differential. We also noticed that the two axle seals were leaking. The fluid was a little low but not out of fluid. I have yet to see any posts for rear diff issues. I've replaced the tranny due to poor service issues with the original warranted owner, and my mech says he probably never serviced anything like the tranny. Due to the extremely high cost for new OEM rear end parts, with limited availability, we are placing a complete used rear end assembly into it with a one year warranty on the parts. Just wanted to see if anyone else has had this problem. I love my Trooper, but it really sucks having them out of production for parts availability. Hold on, I have to call Japan.LOL