Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 BMW X5 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owned a 2021 BMW X5. The contact stated that while sitting in the vehicle and with the vehicle running, it suddenly accelerated on its own. As a result, the vehicle jolted into traffic and collided first with a bicyclist before continuing on to collide with the rear of another vehicle. The bicyclist sustained minor injuries. A pedestrian later reported that they were also struck by the vehicle, but the contact stated that she was skeptical of the validity of their claim. The air bags did deploy. A police report was filed, and injuries were reported. The driver and passenger were both treated on scene by EMS and later evaluated at an area hospital for injuries resulting from air bag deployment. The bicyclist and a pedestrian were both treated at an area hospital for unknown injuries. No warning lights were illuminated. …
The contact owns a 2021 BMW X5. The contact stated while his wife was reversing the vehicle into the main road when shifting gears into drive, the vehicle began to reverse independently while still depressing on the brake pedal. The contact stated the vehicle ran into two different trees and slashed the front driver's side tire. The contact stated the Park Distance Control (PDC) malfunction warning light was illuminated. No air bags were deployed. The driver did not have any injuries or seek medical attention. A police report was not filed. The contact was able to park the vehicle back into his residence. The contact towed the vehicle to a local dealer, who called the manufacturer. The manufacturer sent their engineers to diagnose the failure. The manufacturer called the contact and was informed it was a human error. The failure mileage was approximately 8,000.
The contact owns a 2021 BMW X5. The contact stated that as her husband was stopped at a stop light, the vehicle began to rev after he had taken his foot off the brake pedal without warning. Once her husband placed his foot back on the brake pedal, the revving stopped, and her husband was able to resume normal driving. On a separate occasion, her husband was waiting for a vehicle to move out of a parking spot; the same failure occurred as her husband took his foot off the brake pedal. Her husband was forced to slam on the brakes as the engine continued to rev and the vehicle lurched forward. The contact who was seated in the passenger's seat, shut off the vehicle to avoid hitting the vehicle in front. Her husband restarted the vehicle and drove it home; he then had the vehicle towed to the dealer the next day. The dealer inspected the vehicle but could not duplicate the failure. …
The contact owns a 2021 BMW X5. The contact stated that while driving at various speeds, there was an abnormal grinding and clanking sound coming from the front end of the vehicle. The vehicle was taken to the local dealer, where it was diagnosed that the front differential was faulty and needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was 36,400.
Car was parked in fairly level spot with engine off, gear selector in park position, , key fob not near vehicle. Approx 30 minutes later, I returned to find vehicle approx 30 feet behind parking spot, having apparently drifted into another car in parking lot. No idea how car moved. I believe some electronic release of parking selector allowed car to roll.
While driving on highway/turnpike with cruise control on at 70 mph, drivetrain malfunction warning appeared and lost power. After turning off cruise control and playing around with buttons, could only get car to go about 35-40 mph, top speed with peddle to the floor. Very scary situation in traffic on busy highway. This happened twice about a month apart. First time, had to drive about 10+ miles in right lane with blinkers on to get to an exit. It was late at night and I didn't want to stop on my own. Once turned the car off and on a couple of time seemed to clear the error and I was able to drive city roads at minimal speed limit. Next day car was back to normal. Second time, drove about 2 miles to the exit with the blinkers on. This time when I restarted the car there was still not a lot of power. Drove for a bit but wasn't able to make it to speed limit of 45 mph. …
Steering the vehicle in a low gear causes the vehicle to tremble or shudder. The dealership identified the problem to be the transfer case fluid. In manufacturing, BMW put a fluid which did not meet the specifications of the vehicle. The transfer case fluid is documented in the manual of BMW X5 M50i (2021) to be something which does not require replacement in the lifetime of the vehicle. I raised this issue when the vehicle was under warranty, but the dealership ignored the issue. After the warranty period was over (62,000 miles), the dealer recommended that I replace the fluid to fix the shudder issue. It is a very well known issue, and there is a service bulletin issued to the dealerships to deal with this particular case (SIB 27 02 20). After the fluid replacement, the issue went away. This issue is widely known by the dealership, and it is a safety issue. …
Description of Safety Concern: I am writing to formally submit a vehicle safety complaint regarding the xDrive transfer case on my 2021 BMW X5. While driving, the vehicle exhibits noticeable hesitation, shuddering, and jerking during acceleration at lower speeds and when executing tight turns. This erratic power delivery creates a potential safety hazard, particularly when accelerating into traffic, merging onto highways, or pulling out from intersections, as the momentary loss of predictable drivetrain response increases the risk of a collision. Despite internal technical bulletins from the manufacturer (SI B27 02 20) acknowledging shuddering caused by transfer case clutch breakdown, no official safety recall has been issued. …
My 2021 BMW X5 xDrive40i intermittently fails to start, occurring on approximately 80% of start attempts, and displays the message "Repeat Start Attempt." This has been confirmed by code reading to be a starter-related malfunction. This defect significantly affects vehicle reliability and raises a potential safety concern. BMW previously recalled vehicles equipped with similar starter motors due to starter solenoid defects that could cause overheating, electrical short circuits, and an increased risk of vehicle fire. The symptoms on my vehicle appear consistent with those associated with the previously identified defect. I respectfully request that NHTSA investigate whether the starter motor defect previously addressed through BMW recalls extends beyond the identified production range, including 2021 model year vehicles. …
The vehicle's rear differential has developed significant internal "play" (excessive clearance between gears). This defect manifests as abnormal vibration and inconsistent power delivery to the wheels. The vehicle was inspected by an authorized BMW Technician at Passport BMW . Although I reported hitting a curb (low-speed impact), the official diagnostic report from the BMW Technician explicitly stated that the curb impact did not cause the differential failure. The technician identified the issue as a failure of the internal differential components, which is consistent with numerous reports of drivetrain defects in the B MW X5. Despite the vehicle being well under the 50,000-mile warranty threshold and the technician's own finding that external damage was not the cause, BMW is currently refusing to honor the warranty repair for this critical mechanical component. …
Transmission complaints in other X5 years
Frequently asked questions
How common are transmission problems on the 2021 BMW X5?
NHTSA has 31 complaints about the transmission & drivetrain of the 2021 BMW X5, 28% of the model year's 110 complaints. The component named most often is driveline › differential unit (1 mentions).
Is there a recall for 2021 BMW X5 transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2021 BMW X5, though it has 12 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 BMW X5 transmission problems start?
Half of the complaints with a recorded mileage happened before about 14,000 miles, and 67% before 25,000 miles.
Is it dangerous?
Owners linked 3 crashes, 0 fires and 4 injuries to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.