This may be of interest to someone I have a 2010 X5 40D I have only had it a few weeks but as i got used to it I detected what I thought was a noisy NSF wheel bearing between 50 and 60 MPH. My local BMW agent agreed and changed the wheel bearing but it made no difference It turned out the last BMW garage that had been trying to sort this noise out had changed the gearbox the transfer box and the front diff. The area technician got involved and they put a "Damper" on the NS engine mounting and the noise has gone. So if you have what sounds like a gear train or wheel bearing noise you could need a damper.