2020 Mercedes-Benz GLC 300 Transmission and drivetrain Problems
- Complaints
- 4about this part
- Share
- 6%of 70 total for the year
- Median mileage
- —not reported
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 4 complaints about the transmission and drivetrain of the 2020 Mercedes-Benz GLC 300, 6% of the 70 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 have had my car for almost two years. This problem has been on-going the whole time. It happens intermittently, I never know. I will be driving it and usually when I am making a turn or pulling onto a main road, you press the gas to go and the car hesitates and makes a loud brooooooooom sound like it is trying to go or figure out what to do and if you are pulling out onto a main road with on comming traffic, this is dangerous. We have seen information that on the 2019 and 2018 GLC300's this has been documented, my car is a 2020 but it's the same thing. …”
NHTSA complaint #11737705, filed 2026-05“It took a few minutes to be able to completely turn left out of a shopping center while waiting in line. When finally able to turn left, the car stalled into what appeared to be neutral where I had no control to increase speed and was turning very slowly. Oncoming traffic from both ways were coming and luckily stopped on-time. I had to turn off the entire car and restart in the middle of the road in order to be able to drive again. There could've been a massive collision if cars were not paying attention on both sides. …”
NHTSA complaint #11461938, filed 2022-04“Winning noise in rear end. We bought used noticed noise getting loader. Took vehicle to dealer. We were informed the rear Differential was bad and would have to be replaced. Vehicle has 61,198 miles on it. Wife drives car around town and on trips out of town. i was told they would have to get replacement form Germany. around $9,088. Dealership has helped with splitting cost $4,544.00. After checking around seems the Mercedes is having some problems with this part. When i escalated to Customer care at MB it took (4) phone calls from me to finally get a response from them. …”
NHTSA complaint #11554322, filed 2023-11“My 2020 Mercedes-Benz GLC 300 triggered check engine light with code P06DA (engine oil pressure control) at 40,000 miles. The failed component is an oil pressure control sensor/solenoid worth approximately $200. However, due to Mercedes-Benz's engine design (M264 engine), the entire engine must be removed from the vehicle to access and replace this part. Repair estimate from authorized Mercedes-Benz dealership (Mercedes-Benz of Stevens Creek): $8,391. SAFETY CONCERN: Loss of oil pressure can cause catastrophic engine failure while driving. …”
NHTSA complaint #11746524, filed 2026-06Related service bulletins
- 11038187Sep 26, 2026Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission…
- 11037987Sep 14, 2026Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load…
- 11037616Sep 4, 2026Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission…
- 11036077Aug 5, 2026Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case is necessary, all supporting…
- 11035780Aug 4, 2026Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global supply constraint. 236.17 ATF 1L and 5L…
- 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…
- 11033050May 22, 2026Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline…
- 11032736May 15, 2026The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no…
- 11028834Feb 13, 2026Complaint Check engine light on with the following fault is current in the VGS Control Unit: P084300 Oil pressure sensor 'A' has a short circuit to positive stored in VGS control…
- 11028813Feb 12, 2026Complaint The vehicle cannot disengage “P” (Park), and a red warning message appears in the instrument cluster. Cause Only vehicles with transmission NAG3C 725.0 and engine M264…
Transmission and drivetrain: other model years
Other parts of the 2020 Mercedes-Benz GLC 300
22 complaintsOther or unknown
15 complaintsBack-over prevention (rear camera)
7 complaintsElectrical system
6 complaintsForward collision avoidance
6 complaintsExterior lighting
5 complaintsSteering
5 complaintsFuel system
4 complaintsBrakes
3 complaintsBody and structure
3 complaintsAir bags
2 complaintsVehicle speed control
2 complaints
← All problems reported for the 2020 Mercedes-Benz GLC 300
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