Table 1 shows two common power train related problems of the 2010 Mercury Mountaineer.
| Problem Category | Number of Problems |
|---|---|
| Power Train problems | |
| Differential Unit problems |
Pulled into parking space, placed shifter in park, turned off ignition, released brake and vehicle rolled backwards as if not in park. Attempted to restart vehicle and no response. Set parking brake. Could not get vehicle to lock into park, shifter moved regardless of brake on or not and would not start. Moved shifter through entire range of gears and returned to park, vehicle still would not start and park would not hold. Called dealer and was told to have it towed in. Returned to vehicle and tried once more and it started and proceeded to respond normally. Vehicle taken directly to dealer who could not find any problem or cause of preceding situation. On two subsequent dates (most recent 5/25/2012), vehicle was backed into a parking space, placed in park and ignition turned off. When an attempt to restart vehicle was made there was no response. Park appeared to hold normal, but unable to engage ignition. Dash lights, chimes and all electrical components appear to work normal but was still unable to engage starter. Again started process to have vehicle towed to dealer. After approximately 30 minutes to an hour of sitting (with no other action) vehicle started normally. Again dealer at a loss for cause and cannot effect repair since unable to recreate problem. Concern is for transmission/ignition interlock failure or other action that could result in damage or injury.
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.