I think that s the pto bearing side, when i got mine i had a blown pto bearing, after 6000 miles, but that bearing was common on going out on the 94 580's and if you stay under 9000 rpm you shouldn't have any trouble keeping that bearing, but if you go above that you'll probaly have to change that bearing every year. i don't know if this is what happend to urs, but thats what hapend to mine so i thought id let ya knwo
Ride Polaris!