Tom - I repacked the front bearings, tightened everything, and re-checked all - still loud drone. It appears it is coming from the rear...when I apply the brake it reduces slowly towards goes away, I carefully applied the parking brake while driving and the result was also drone went away. I'm pretty convinced that the issue is related to the rear - possibly the ebrake. I'm bringing it to me favorite MB indy tomorrow. I simply don't have the time. This kind of bums me out because after installing new rotors and calipers up front, the 560 has never driven better - absent this drone of course.

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Woody