There are 1 stored owner reports matching the powertrain & transmission leading-label group for the 2021 BMW 4 Series in our NHTSA-sourced dataset. These are unverified consumer reports and may not reflect confirmed defects.
This group counts stored reports whose component label starts with one of this site's matching prefixes, ignoring case. Each matching report counts once within the group. Components mentioned later in the label or only in the narrative are not searched. How component counts work
Loaded 1 of 1 matching reports.
Open the full vehicle complaint log (all categories)The contact owns a 2021 BMW 430I. The contact stated while stopped at a traffic light, the light turned green; however, when the accelerator pedal was depressed, the vehicle failed to respond as intended. The contact stated that the power train warning light was illuminated. The contact turned off and restarted the vehicle, shifted to drive(D); however, the vehicle failed to respond. The contact had the vehicle towed to a dealer to be diagnosed. The dealer determined that the rear differential oil had leaked out causing the differential to seize. The contact was informed that the rear differential needed to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 33,000.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
NHTSA source checks for this vehicle year
Checks are recorded separately for each dataset, not for the whole page. Dates use UTC. A missing check date does not mean no records exist.
Vehicle import recorded: Aug 30, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.