One problem related to engine noise has been reported for the 2011 BMW X5. The most recently reported issues are listed below.
Drive shaft failure. . . On highway driving 70 mph and the car became uncontrollable. Pulled off the side of the road and stopped the vehicle. Car then would not go into drive only neutral. Car towed to performance BMW . I had previously complained about how loud the cabin was with engine noise and a slight vibration when stopping. Now the drive shaft is ruined as well as leah in oil housing, pan etc.