Reply by RussellAP

Sorry about all these comments, but if you call Ridgid and let them listen to the sound, they’ll probably send you 080035003701 Arbor Assembly. Or you could return it, which is a pain. I actually had to remove the motor assembly from my 4512 to get the thing out of the box because I had no help, very heavy unit.

-- Failure does not stop me, it makes me try harder..... because I'm crazy.