Originally Posted by that_guy

Over the past year or two I wound up taking my rear diff apart twice. Once to put a lsd carrier in and then another one from a junkyard 03 that I swapped out my axle with to get rear disc brakes (swapped my lsd carrier into that axle too). I don't know how many miles were on the 03 rear end from the junkyard, but my original rear end had 210k or so at the time. The timken bearings from factory in both of those rear ends were like new. So aside from some seals that are old and backlash in gears over time I bet you're set for at least a few hundred thousand more miles.