I just replaced my axles at 100 thousand miles due to a slight steering wheel vibration under acceleration. Also I notice one of the dust seals just started dripping slightly after some off roading a couple days before I changed the axles. After cleaning the dust seal good I could see that the actual rubber seal and springs that keep pressure on the axle shaft were in brand new shape. The OEM seals are excellent quality. Under closer inspection I could see that the seal was a tiny bit cock eyed. I tapped it back into flush. No more drip. If they aren't leaking and the rubber areas look good then they are fine. You can get them out by prying carefully with a long screwdriver without touching inside the diff.