Update #2: An appliance repair person came to my house, and being baffled, he called Amana's "pros-only" repair hotline, to be told that it was the brake pads. Wishing to avoid the massive labor costs for a multi-hour teardown to replace $10 of brakes, I paid the trip charge, ordered brake pads, and replaced them--sure enough, they were pretty well worn. Squeak persists.
Any thoughts? :-(