I suggest checking the drained oil for excessive wear metal and remove the carrier and inspect the carrier bearings. If there is any pitting or any grooves in the bearing races then I recommend replacing all of the bearings and seals. When you put the diff cover back on put a very strong magnet on the inside of the diff cover to catch any future wear metal. If you're interested in having the work done and you don't mind a 4 hour drive, I can do this for you. PM me if you're interested.