Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2010 Mercury Mariner owners, lightly cleaned up (personal details are redacted by NHTSA).
I was driving when it felt like the vehicle was reving in park then the "wrench" icon appeared on my dash. I went a couple blocks & my vehicle felt like it wasn't shifting automatically as it should. I pulled over & turned it off. It started right back up with no lights on, I went half a block & stopped at a stop sign but while stopped the engine reved up. I was worried I was going to be in an accident. Then the "wrench" light came back on, since I was close to home I figured I'd just try to get home. About another block, the check engine light came on & was making strange noises. I kept my vehicle at about 5-10 mph & got it home. My car was very jerky.
Tl* the contact owns a 2010 Mercury Mariner which was being towed by a 2004 fleetwood tioga montara. While driving approximately 60 MPH, the contact noticed smoke coming from the hood. The motor home was pulled over, the contact opened the hood, and noticed that the transmission overheated without warning. The vehicle was taken to chuck colvin Ford Nissan (1925 n hwy 99 w, mcminnville, or 97128, [phone]), but was not diagnosed or repaired. The manufacturer was made aware of the failure and stated that the failure was a known occurrence with the transmission at approximately 50,000 miles. The failure mileage was approximately 56,000.
Our 2010 Mercury Mariner had a clunking and loss of power on two different occasions. The first time we brought it to the Ford dealer and he checked codes, etc, only to find nothing. The clunking or loss of power did not came back for a while. Several months later while driving home from work, the clunking sound appeared again, there was an evident loss of power and the orange wrench displayed on the speedometer indicated an issue. I had to work on getting the vehicle up to speed and power again, slowing the traffic in back of me down. The vehile was purchased a year ago, almost to the day and has approximately 52,000 miles on it. I called the Ford dealer who made arrangements to bring the vehicle in for a check up. Based on what I'm reading, these are known issues with a throttle? Not certain if there's a recall or not but will certainly find out. …
I was driving at 65+ MPH on expressway - vehicle stopped accelerating and a violent shaking of the vehicle occurred forcing me off the highway - at this time notice an image of a "wrench" lit up on dash -- I was able to get vehicle to the dealer - not worried due to I still had 2000 miles left on warranty, only to be told this is not covered under warranty. My question is this is huge safety issue and should under no questions be a charge to the consumer. I was charged 309.20 to replace the throttle body motor and assembly. After much research this is an ongoing problem with many of the Ford vehicles. Attached is the invoice that I had to pay. I have tried to obtain the zone rep for my area and I am having trouble getting this info from my dealer. I am still investigating as to how to obtain this info as I believe someone in higher position then dealer needs to be aware.
Intermittently loosing power, intermittent wrench light. Power loss happens when going up hill from a stop or even when at a rate of speed on the freeway. Goes completely limp, but does not shut off. Almost rear ended by a semi yesterday morning. The wrench light goes off and stays off for a bit once you shut the car off, making diagnoses very hard. What once was so intermittent it was thought to be a fluke, is happening with more regularity. And I see other complaints but no recall for this issue, so I know I am not the only one having this extremely dangerous issue.
While driving home from work last night, vehicle suddenly declined in acceleration...started jerking and illumination of a "wrench" symbol appeared on the dashboard...never had any problems with this vehicle in the past besides routine maintenance...scared to drive it until problem is solved..
I was driving my 2010 Mercury Mariner , when the engine lite came on with a little wrench lite. My car started to lose power and I could not get it to pick up power. I pulled of the road. I turned off my car, I didn't know if it would start again .very scary.I have only 86000 mile on it .
Car stopped running wrench light came on started motor put it in gear tried to go regular pace car did not go it is very slow no gas peddle turned it off let set for 2 hrs. Started back up runs OK but check eng. Lite came on called dealer
lost of steering control because of power steering failed. And caused elec. system to go nuts
I purchased 2010 Mercury Mariner at the end of May 2010, approximately 21 weeks after purchase date my transmission failed; very harsh engagements, vehicle jerks hard between gears, looses power and pops forward when driving steady speed and when approaching an intersection to stop or turn. Safety concerns due to unknown if power failure will occur when there is oncoming traffic or if vehicle will pop me into oncoming traffic or hit someone ahead of me in traffic. Transmission issue also causes poor gas mileage. Ford dealership replaced transmission in 10/16/10 (13 days with dealership) and stated vehicle issues were corrected. …
Transmission complaints in other Mariner years
Frequently asked questions
How common are transmission problems on the 2010 Mercury Mariner?
NHTSA has 60 complaints about the transmission & drivetrain of the 2010 Mercury Mariner, 22% of the model year's 270 complaints. The component named most often is automatic transmission (3 mentions).
Is there a recall for 2010 Mercury Mariner transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2010 Mercury Mariner, though it has 2 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2010 Mercury Mariner transmission problems start?
Half of the complaints with a recorded mileage happened before about 52,000 miles, and 7% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.