There are 1 stored owner reports matching the powertrain & transmission leading-label group for the 2010 Mercury Mountaineer 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)REAR DIFFERENTIAL IS FILLING WITH WATER PASS THE FILL PLUG. THIS IS A GARAGE KEPT CAR AND NEVER OFF ROAD NOR DIRVEN IN DEEP WATER. FIRST TIME DISCOVERED AT 22000 MILES AND THE DEALER REPLACE THE PINION SEAL AND OIL, BUT COULD NOT FIND THE CAUSE. DIFFERENTIAL NOW MAKING NOISE AND AGAIN FULL OF WATER PAST THE FILL PLUG. SEARCHED ONLINE AND FOUND SEVERAL PEOPLE WITH THE SAME PROBLEM WITH FORD PRODUCTS. DEALER CANNOT FIND OR NOT WILLING TO FIND THE CAUSE. CALLED FORD AND THEY OFFER LITTLE TO NO SUPPORT. GUESS THEY ARE WAITING FOR THE DIFFERENTIALS TO LOCK UP AT HIGHWAY SPEED AND KILL A DOZEN OF SO PEOPLE.
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: Apr 28, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.