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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53940
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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S550: Michael, I have a 07 MB S550 with 120K miles. I was

Customer Question

Hi Michael, I have a 07 MB S550 with 120K miles. I was driving the car and suddenly it felt as if the car is getting stuck in a gear. I turned the car off, turned it on again, and it worked fine for a minute or so but then it was as if the car would go into neutral and or get stuck on a high gear.
Do you know if this is a common issue and what can be done about it? Do I need to change the transmission?
Submitted: 2 years ago.
Category: Mercedes
Expert:  Marty replied 2 years ago.
Hi, the common problem is a failed speed sensor in the transmission. The sensor is part of the electro hydraulic control unit. To repair the fault the control unit will need to be replaced. The control unit is mounted inside the transmission. Estimated cost to replace the control unit is $1500. The repair should be done at the Mercedes dealer as there is programming required upon installation. This is a very common problem on the Mercedes transmission.
Let me know if you have any questions.