Two problems related to differential unit have been reported for the 2003 BMW X5. The most recently reported issues are listed below.
The contact owns a 2003 BMW X5. While the contact was driving 50 mph he noticed a clicking sound coming from the front of the vehicle. When the contact attempted to accelerate the rpm's would rise but the vehicle would not move. The contact did not notice any differences in the vehicle beforehand and was not in a crash due to the failure. The vehicle was towed to the dealer where the contact was informed that the transmission and the differential failed. The VIN is unavailable. The current and failure mileages were 48000.
Driving BMW X5 at 50 mph, front differential locks up taking vehicle from 50 mph to approximately 25 mph in about 1 second then differential fails. Gear oil sprayed on hot exhaust and engine, car would not move forward, passenger (my wife) jumps out when we stopped thinking car was going to catch fire (smoke and strong burning smell from oil). Dealer had car towed to shop, had to replace forward drive train. Car was in shop 4 days. My wife will not ride in car again, she almost impacted the dash when axel locked up, had road been wet or icy, we could have very easily lost control. Had a vehicle been behind us, very likely they would have run into the back of the car it stopped so fast and unexpectedly. Felt like we ran over a large tree in the road but the road was perfectly clear. Immediately traded the car and bought another vehicle, believe ntsb needs to be aware of the failure and see if it happens elsewhere, very scary to have car wheels lock up on the highway at any speed.