TL* THE CONTACT OWNS A 2006 BMW X5. THE CONTACT STATED THAT WHILE DRIVING APPROXIMATELY 5 MPH THE CONTACT NOTICED A GRINDING NOISE COMING FROM THE FRONT END OF THE VEHICLE AND THE TRANSMISSION FAILURE LIGHT ILLUMINATED ON THE INSTRUMENT PANEL. THE CONTACT HEARD A LOUD BANG IN THE REAR OF THE VEHICLE AND NOTICED BLUE SMOKE EMITTING FROM THE TAIL PIPE. THE VEHICLE WAS TOWED TO THE CONTACTS HOME AND LATER DRIVEN TO THE DEALER FOR DIAGNOSTIC TESTING. THE TECHNICIAN DIAGNOSE THAT THE TRANSFER CASE ASSEMBLY NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE APPROXIMATE FAILURE MILEAGE WAS 74,000.