it bearly leaks and i drive it in creeks consantly so there is always water getting in the axle. i change diff lube once a month. dont you have to cut an axle tube off to make a jig to press the bearing out???
water wont go past a good bearing and seal. the water is getting in through the axle vent. you need to get this-->
http://www.marlincrawler.com/axle/rear-axle-parts/axle-breather-kit