Right before my Michicagn trip last week my AC compressor started getting a bit clangy. It turned out to be an easy repair. The problem is that the clutch hub bushings had fallen out. A replacement can be purchased from rock auto for $35, but I was lucky to have a spare compressor I pulled one off. The one on the left came of my car while the one on the right came off the spare. You can see how the 3 rubber bushings are missing.