Vehicle Symptom: The vehicle exhibits a persistent rough idle and engine hesitation specifically when at operating temperature. This issue is most prevalent during "Auto Start/Stop" transitions and while idling in heavy traffic. The engine feels as though it may stall, creating a significant safety concern regarding predictable acceleration and vehicle control in live traffic. Safety Risk: The instability of the engine performance creates an unpredictable driving experience. There is a high risk of the vehicle stalling or failing to accelerate properly when restarting from a stop, which could lead to a rear-end collision or leave the vehicle stranded in a dangerous intersection. Furthermore, despite these clear drivability issues and the engine's erratic behavior, the vehicle has not illuminated a Check Engine Light (CEL), depriving the driver of a necessary safety warning regarding these malfunctions.

Component/System that failed: The rear differential failed internally, causing the left rear axle to separate from the differential housing. BMW’s own service center confirmed there was no external damage or outside force involved. The defective parts are currently with BMW of Manhattan and can be made available for inspection. Safety risk posed: This failure created a significant safety hazard, as drivetrain separation while in motion can lead to loss of vehicle control, wheel lock, or a collision — especially at highway speeds. Fortunately, no accident occurred, but the risk was high. Was the problem confirmed by a dealer? Yes. BMW of Manhattan confirmed the failure in service invoice #1201464. Their technician wrote: “Found left rear axle is popped out of differential. No signs of damage or outside influence. Differential is internally faulty.” The dealership replaced the rear differential and associated components under warranty. Was the vehicle inspected by others? The vehicle was only inspected and repaired by BMW of Manhattan, an authorized dealership. No police or insurance inspection occurred. Warning signs before failure? Yes. The vehicle was brought to the dealership on four separate occasions before the failure due to: •Loud noises from the rear axle area, •causing the abnormal wear and tear of tires , and •Erratic driving behavior. Each time, BMW’s service team stated the vehicle was “in healthy shape.” Additional context: Despite this failure being documented as internal and not customer-induced, BMW North America has refused to accept responsibility or honor a buyback request. The vehicle is used for business purposes under Cuatro Sons Inc. and has now been taken off the road due to the safety risk and unresolved concerns about reliability. We are seeking NHTSA’s investigation and intervention.