I have a Dec 2014 S85 with 25k miles that has made the milling sound pretty loud the last 3 months. I've been putting up with it but finally broke down and called my service center and made an appointment, as it has reached the point that passengers are commenting on it and it's detracting from my enjoyment of the car. I'm expecting them to change the motor. Have they finally fixed this issue so that my replacement motor won't have it in the future? I don't hear much talk about this any more but a year or two ago it was a big issue. I assume I will get a rebuilt motor? Was it determined to be a bearing failure? What change do they make in rebuilding these that prevents the issue from returning?