This sounds pretty close to what I had to do on every creeping one that came in. Blow out the dust,use old cheap Wally World brake cleaner,install a new belt and 2 or three shims behind the rear clutch.Belts were usually too glazed and burnt to reuse from all the creeping. Hopefully this will last for awhile,BUT I've had some that would come back 6 months or a year later for the same thing again. Seems like I had more problems on the 2001-2002 Sportsman 500 than any other year on this.