Get up on the roof,(Be sure to take a can of silicone spray with you.) remove the four phillips head screws holding the shroud on and remove it. Find the squirrel cage and look at the shaft where it comes out of the motor. You'll most likely find a good amount of dirt and lots of rust. Clean the shaft and squirrel cage of any debris and dirt and liberally apply the silicone spray. Have someone turn on just the fan, no A/C and see if it quiets and/or stops completely. If it quiets, turn everything off, clean the shaft and cage again. Spray again and try it again. These A/C units are probably the most neglected part of our coaches. They should be lubed just like your coach, at least annually....Dennis