My 2007 mb S550 base model stalled as I was merging on to the expressway in heavy traffic. After sitting on side of the road for 20mins, I started the car and it was making a whining noise and when I accelerate the noise gets louder. I drove the car to the nearest Mercedes-Benz dealership. I was told that the transmission needs to be replaced. The car has been serviced with Mercedes and only has 100K miles. This will cost $7,800 the service guy stated that this should not be happening on this car but unfortunately he stated that he has seen this before.

- Saint Louis, MO, USA

The contact owns a 2007 Mercedes-Benz S550. While driving approximately 1 to 6 mph, the transmission gears made a thumping sound without warning. The issue recurred numerous times. The dealer diagnosed that the transmission had to be replaced. The vehicle was taken to a transmission specialist where it was diagnosed that the valve body needed to be replaced. The manufacturer was notified. The vehicle was not repaired. The approximate failure mileage was 76,000.

- Arcadia, CA, USA

The contact owns a 2007 Mercedes Benz S550. The contact stated that while driving at 45 mph, the vehicle began to loose power and suddenly stalled without warning. The vehicle was taken to a dealer where it was diagnosed that the conductor plate and valve body failed and needed to be replaced. The vehicle was repaired but the failure recurred at 100,000 miles. The manufacturer was not notified of the failure. The failure mileage was approximately 67,000. The VIN was not available.

- Charlotte, NC, USA

Vehicle becomes stuck in gear while driving down the road. Will not shift, sometimes you don't have enough power to move quickly. For example vehicle was stuck in 6th gear after leaving the highway. I could not accelerate to move the car. I had to shut the car off to reset the computer to get the car out of 6th gear. This has happened at least 10 times over the past 3 month period. Many other owners of this car have experienced the same transmission failure and that is very dangerous because the car lose power when it is stuck in a gear. The only way to fix the problem is to shut off the car and restart it. Mercedes Benz should be held responsible for this issue.

- Royal Palm Beach, FL, USA

2007 S550, 7-speed automatic transmission, 57,000 miles. Started about 6-8 months ago. Experiencing very rough jolting type shifting, most commonly occurs after being parked on an incline or decline. Occurs when driving up or down an incline. Also, occurs on the freeway or after using cruise control. Transmission shifts from first to second gear and stays there until it's restarted. Requires turning off the car waiting a few seconds and restarting to reset the gears. Check engine light now starting to come on.very dangerous when driving in heavy traffic or on the freeway. After researching this issue I cannot believe it simply hasn't been recalled. This is a very dangerous issue...I will not allow my wife to even drive the car unless I am with her.----many forums are suggesting a valve body replacement. Appears to be a very common issue with these vehicle. Located a class action lawsuit that unfortunately was dismissed due to the complaint citing fraud. I don't believe Mercedes sold these vehicles knowing the transmission was faulty. I would just expect them after receiving numerous complaints to offer their clients a repair option via recall. To date I am not aware of one. I have owned 4 Mercedes in my lifetime, 38 years old and had a few minor issue here and there but never anything like this. Service has always been great but now that I am out of warranty I am left out in the cold. Not good for business in my opinion and very unsafe for anyone on the road while a Mercedes owner is experiencing this issue.

- Porter Ranch , CA, USA

The contact owns a 2007 Mercedes Benz S550. The contact stated that while driving 30 mph, the vehicle failed to accelerate without warning. The vehicle was restarted and functioned normally. The vehicle was taken to a private mechanic where it was diagnosed that the transmission valve body with electrical plates needed to be replaced. The manufacturer was notified of the failure. The vehicle was repaired. The approximate failure mileage was 160,000 and the current mileage was 190,000.

- Spring , TX, USA

I was driving my S550 and came to a red light. I stopped at the light and when it turned green, I took my foot off the brakes and pressed the accelerator, but there was to response to pressing the accelerator. The car rpms were increasing but the vehicle was crawling at less than 5mph. This led to me pulling over and parking the vehicle and turning it off. I waited 5 minutes and then restarted it and it began to work normally. The second time this happened was while making a left turn, I pressed the gas pedal and there was no response and the car was revving but traveling less than 5 mph with oncoming traffic having to stop short to prevent crashing into me while I was making the left turn. This was again resolved with me parking the vehicle, turning it off and then restarting it. After the second time this occurred out of no where I decided its a very dangerous safety issue.

- Shirley, NY, USA

The car stopped accelerating and then quit running. The conductor plate in the transmission failed. This is a known safety defect that Mercedes-Benz has ignored.

- Sacramento, CA, USA