So Im wondering since Ive pulled this 8" chunk and there is no visible issue and everything moves smoothly, not one bad tooth on the ring or gear, could a pinion bearing still be bad. Before I pulled it, there was a good leak coming from the pinion housing, up front. Ive read over and over about a seal failing because a pinion bearing has failed. But the test I see for checking the condition of the bearing.... grabbing the drive shaft and looking for play in the yoke by trying to shake the driveshaft....have left me seeing otherwise. Every time that I have yanked around on the driveshaft, I have no play, no movement, just small back and forth turning movement(the backlash). So my question is why would this seal fail? Age? After tearing through this entire rearend, redoing the entire brakes, new axle bearings, I cannot figure out what the issue would be.