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 2006 Mercury Mountaineer owners, lightly cleaned up (personal details are redacted by NHTSA).
My car has had a continuing problem with the transmission. It shifts roughly and lurches when beginning to move. For example, when stopped at a stoplight, and then beginning to drive, it will lurch, jolting the passengers. Our driveway is sloped toward the street. When I park the car, I always set the emergency brake as well. The car always rolls a few inches before the brakes lock, even though it is stopped and in park. On sep. 4, 2009, my mother borrowed my car to go to lunch. She couldn't find the emergency brake release. She put the car in park and got out to locate the emergency brake. She found it and released it. The car popped into reverse and rolled backwards to the street. The door knocked my mother down and she hit her head hard enough to sustain a closed head injury with minor bleeding in her brain. …
Truck cooling system died which caused the truck to catch fire while driving down the highway, smoke poring out, state troopers had to assist us. My daughter was scared to death and now refuses to get back in the truck even though we got a new engine. To make matters worse we spent 3000 on and engine...500 on cooling system and had the transmission reprogrammed. The truck is still have major problems and now for says it needs the transmission rebuilt or replaced. All of this is out of pocket. We cant even trade it in bc they will only give us 1/2 of what we paid for it 2 yrs ago. Nightmare and makes me sick that Ford doesn't care.
The gear shaft will stop my car from starting when I turn it off. It will also make my car vut off while driving..the button on the gear stick will get stuck and I am able to shift gears...when the car is not started and my foot is not on the breaks. Even when the button is not stuck, it still will get stuck in park and wont let me start my car..a recall should be started..because I have seen others on here with similar complaints..so its a manufacturing accident not the consumer.
2006 Mercury Mountaineer slipped out of parked in driveway and hit mother inlaws 2005 GMC envoy. This is one of a hand full of times it has slipped off park. Took it to the dealership 3 times and nothing, now I am fighting with grand ledge Ford, grand ledge, mi to get it fix or replace the transmission before someone get seriously hurt or even dies. This is a very scary situation and needs to be recalled as soon as possible.
Tl* the contact owns a 2006 Mercury Mountaineer. While the vehicle was stationary, it would not reverse when prompted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was 154,758.
2nd Mountaineer owned transmission will not shift in low gears and unresponsive. Stalled in town and on highway at high speeds almost causing collisions several times after becoming unresponsive while driving.
I received my vehicle 1/18/2006 a Mercury Mountaineer. On my survey that I returned to Ford in March of 2006, I told them that I hated their " slip-o-matic " transmission. I do not have all the visits documented but the second problem we had was the vehicle would come to a stop at a stop light and then a few seconds later you would feel a "thud" like you were hit from behind by another vehicle. We had the transmission reprogrammed and the valve replaced and that problem seemed to be resolved. But the slipping through the gears continued to be a persistent problem. It is almost as if when you pull out into the highway that you are in suspended animation for 1 to 1.5 seconds. This is particularly unsettling when crossing several lanes of traffic from a stopped position... …
Have sent a complaint recently no one has contacted me I've seen on line hundreds of complaints due to faulty transmissions on Ford, and Mercury Mountaineer ESP 20001- thru 2012 models and had a 2004 last yr. I had to send to junkyard because transmission was bad and would also stop while driving ESP. On highways at speeds over 55 MPH many close calls and lucky I wasnt injured or killled due to trouble with transmission not shifting and becoming unresponsive to where it had to be towed several times when transmission became unresponsive now my 2006 Mountaineer AWD has similar problems and every one I have tried to purchase as a replacement also has had problems with their transmissions failing so need some advice as to what can be done to correct these issues!.....as in past I stated it fails loses power and transmission fails while driving on highway after slowing down or coming to …
I bought my 2006 Mercury Mountaineer April 26, 2006. I started having the transmission problems December 2006. When you put on breaks to stop you hear a thud and the vehicle will actual throw you forward in the seat. It feels like you might not actually stop when it first happens. This happens daily. The fist time I took the vehicle in and left it with them, they drove it and said they did not find anything. January 2007 I took the car back to them and they did dive it and have the same problem. The called Ford and Ford told them there was a recall on it and they needed to put it on the computer and do a recalibrating. They did this and the problem was gone for a week and it returned. I took it back to them and they replaced a part in the transmission, this lasted a week and it started the same thing again. I am now still fussing with them about getting if fixed. …
2006 Mercury Mountaineer v8 AWD--when shifting from park to drive or reverse it "clunks" hard into gear. The wrench symbol and the engine symbol light up. The vehicle also drives hard as if it isn't changing gears. The dealership will only say that the Ford TSB recommends replacing the transmission fluid and filter, then resealing with foam seal first but refuses to give me an actual diagnosis of what is going on with the car. They can not tell me the real problem and insist that we will have to work through the various steps on the Ford tsbs which May or May not work (by their own admission) and the cost of final repairs is completely open ended. When I questioned what we would try next after the transmission fluid/filter replacement (because I was skeptical about this causing the issue on a vehicle with only 43,000 miles) they had no answers at all. …
Transmission complaints in other Mountaineer years
Frequently asked questions
How common are transmission problems on the 2006 Mercury Mountaineer?
NHTSA has 39 complaints about the transmission & drivetrain of the 2006 Mercury Mountaineer, 33% of the model year's 117 complaints. The component named most often is automatic transmission (23 mentions).
Is there a recall for 2006 Mercury Mountaineer transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2006 Mercury Mountaineer, though it has 1 recall 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 2006 Mercury Mountaineer transmission problems start?
Half of the complaints with a recorded mileage happened before about 53,000 miles, and 30% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 2 fires and 1 injury 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.