2021 Mercedes-Benz GLB 250 Transmission and drivetrain Problems
- Complaints
- 3about this part
- Share
- 10%of 29 total for the year
- Median mileage
- —not reported
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 3 complaints about the transmission and drivetrain of the 2021 Mercedes-Benz GLB 250, 10% of the 29 complaints for this model year.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“I purchased this vehicle in May 28 2025. I certified car. I took in for oil change Nov 17-2025. Found out they had lot of issues., left front bushing arm leaking. Rt engine mount leaking. Bad brakes battery low. Bad tire rt back passage side.front wheel axle and rear wheel axle is bad and screw on the engine mount is missing. Screw and leaking..?and the vehicle needed a alignment.”
NHTSA complaint #11708509, filed 2026-01“It appears as if there is an issue with the transmission. In this vehicle. When you come to a stop the transmission has a loud clunking noise coming from left side of vehicle. The clunking occurs when the vehicle downshifts. It clunks from d4 to d3, then d3 to d2 , and again at d2 to d1. I have taken it to the dealer numerous times to have it checked. The service mgr weny for s test drive with me and heard it. I was then told the clunking was normal . I purchased the vehicle as a certified used vehicle from the same dealer . This has been occuring since purchase in may 2024”
NHTSA complaint #11704654, filed 2025-12“In April 2025, my 2021 Mercedes-Benz GLB 250 (81,000 miles) suffered repeated engine issues caused by a cylinder head failure. The dealer attempted a cylinder head replacement, but during their own test drive after repairs, the engine completely seized and failed again on their property. This indicates a severe defect in the engine assembly that risks sudden power loss while driving, which could cause an accident. Prior to the failure, there were warning messages about misfires and rough idle. …”
NHTSA complaint #11668223, filed 2025-06Related service bulletins
- 11037211Aug 29, 2026Complaint Intermittent shift feel or thud/clunk noise perceived, such as a brief jerk or transmission reaction during certain driving situations. May be most noticeable when…
- 11036514Aug 25, 2026Complaint Customers may report one or more of the following: • Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after…
- 11035713Aug 4, 2026Complaint Customers may report one or more of the following: • Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after…
- 11035005Jul 14, 2026Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of…
- 11026832Dec 19, 2025Complaint Oil residue in connector of transmission control unit in dual-clutch transmission models 724.0 and 724.1. Cause As part of the production process, the electrohydraulic…
- 11025648Nov 15, 2025Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse…
- 11024632Oct 29, 2025Complaint Instrument cluster message "4MATIC inoperative". The following fault code may be present in all-wheel drive control unit N15/17: P147354 - Erroneous adaptation of the…
- 11023193Sep 17, 2025Complaint Transmission control unit Y3/8n4 (fully integrated transmission control unit (VGS)) not listed in quick test and/or no communication possible with VGS. Cause…
- 11022048Aug 7, 2025Complaint Transmission limp-home mode with fault message in IC "Gear Change to R Not Possible", the even gears are locked. The concern of transmission limp-home mode disappears…
- 11022045Aug 5, 2025Complaint Customer complaints regarding automatic transmission 724.1 (8FDCT & 8FDCT hybrid) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair…
Transmission and drivetrain: other model years
Other parts of the 2021 Mercedes-Benz GLB 250
10 complaintsEngine
7 complaintsElectrical system
4 complaintsSuspension
4 complaintsBody and structure
3 complaintsBack-over prevention (rear camera)
2 complaintsFuel system
2 complaintsSteering
2 complaintsVisibility (wipers, defrost, mirrors)
2 complaintsWheels
2 complaintsAir bags
1 complaintsBrakes
1 complaints
← All problems reported for the 2021 Mercedes-Benz GLB 250
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology