NHTSA — Power Train: Driveline: Differential Unit Problems

CarComplaints.com Seal Of This Might Hurt


hardly worth mentioning
Crashes / Fires:
0 / 1
Injuries / Deaths:
0 / 0
Average Mileage:
66,375 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2004 Mercury Mountaineer drivetrain problems

drivetrain problem

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2004 Mercury Mountaineer Owner Comments

problem #4

Apr 102012


  • 143,000 miles


The contact owns a 2004 Mercury Mountaineer. While traveling 5 mph in reverse, the contact noticed a thumping sound coming from the rear passenger side of the vehicle. Moments later, the contact noticed that the vehicle would no longer accelerate. The vehicle was taken to the dealer where the rear differential was replaced. The contact stated that the failure was recurring. The current and failure mileages were 143,000.

- Jessup, MD, USA

problem #3

Dec 072008


  • 66,000 miles
Our vehicle was purchased in June 2008 at dealership nearby. We were driving home and there was a grinding and popping sound in the rearend of the vehicle. It was me, my husband, 3 mth old and 2 yr old occupying the car. My husband got out of the car and stated to get the babies out of the car in a hurry it was on fire. We got the babies out and ran in to call 911 and the fire dept. The fire was contained and took to a local garage at that time I contacted my auto insurance to see if this was something that would be covered. They sent an auto adjuster out to look at it. Our insurance did help to repair the rear differential. The rear differential had got so hot it exploded causing the fire. Then after the car was repaired we began to have problems again at that time I contacted Ford Motor Company. They explained they could not replace the car but if I took to a local Ford dealer for diagnostic they may consider repairing. So I did and the whole transfer case has to be replaced and Ford is not paying for the cost. I just don't want this experience to happen to anyone else and to risk their lives just driving this car as a result to a fire. The fire was close to the fuel tank. I don't think this car is safe for us to drive I always have that fear in my mind and worrying about my babies. Now I have this new problem with the vehicle to deal with. I have talked to several people and one particular company that has the same type of vehicles with the same problems. Something really needs to be done about this.

- Pennington Gap, VA, USA

problem #2

Feb 132008

Mountaineer 6-cyl

  • Automatic transmission
  • 46,500 miles
Whining noise coming from rear end (rear differential) of vehicle. It appears that Ford Motor Company is aware of this problem but are not willing to repair this issue for free. This problem is widespread, over many model years.

- Bronx, NY, USA

problem #1

Apr 202004

Mountaineer 8-cyl

  • Automatic transmission
  • 10,000 miles
I purchased my 2004 Mercury Mountaineer in Oct 2003. The vehicle was making a roaring noise, once taken in Ford replaced the rear differential and rear drive shaft, also complained of rough shifting of transmission around 30-35 mph changing from 2nd to 3rd gear. The solenoid was replaced, additive added, many reprograms but after 6 trips to dealer still is not corrected. 18 months later roaring noise appeared again and same rear drive shaft was replaced. The vehicle has less than 30,000 miles.

- Shelbyville, TN, USA

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