sounds like there may be more than one issue. but hard to pin point anything
any noise without auger engaged?
pull belt cover, move idler bearing away from belt and rotate by hand. any roughness? should be smooth
check for anything hitting/rubbing first
look for missing/wearing of paint in auger and impeller housings
then if nothing is obviously hitting 1 way to help narrow the area without taking it apart is to get a mechanics stethoscope from harbor freight (4 or 5 bucks). same a a doctors but it has a small metal pipe attached to the end. with auger running touch the end to the different bushings and bearings and you will notice a substantial difference with the bad one. if it is loud enough you would probably be able to feel it in a bearing once you take the machine apart but its nice to narrow it down.