I have a baffling noise in the rear of my 540i.

It's rotational, whirring, rubbing sound similar to a warped rotor. It changes with vehicle speed and appears on both sides or center of the car while driving.

I jacked the rear up, removed tires/wheels, and let her idle in drive. There is slight noise from both rotors with calipers removed, but it seems so quiet I'm not confident I've pinpointed it to there.


Could it be something else? Perhaps by removing the load from the suspension components I have masked it?