The "milling noise" started on my S85 Dec'14 delivery at 17k miles in July, and the Scottsdale service center told me I would be added to a wait list for DU repair, pending release of a factory repair process. I now have over 21k miles and have not been contacted yet for the repair. The noise level seems to be getting louder, can be heard inside the car with the windows up and stereo on, and continues up to 40 mph! By the time it goes in for service at 25k miles, I will request that a repair or replacement be done.