maraschwarz44

GLK transmission problems Any ideas

My 2011 Mercedes GLK diesel is having some serious transmission problems. 187979 km on the clock. Basically, the paddle shifters don't work at all, and the automatic gearbox slips and shifts really rough. Sometimes I hear grinding noises when it shifts, and the paddles are super slow to respond even when they do work for a sec. Now the gearbox is stuck in emergency mode. Checked the error memory, and it points to a defective transmission control unit. Shop is quoting around 1000€. Anyone else seen this?

4 comment(s)

Transmission control module issues are common enough. Have you checked the wiring harness for any obvious damage or corrosion? Before replacing the whole unit, it might be worth inspecting the connections.

Good point. Where exactly is the transmission control unit located on this model? And is checking the wiring something I can realistically do myself without special tools?

It is often located inside the transmission itself, which means you'd need to drop the transmission pan to get to it. Given your symptoms and the error code, a defective control module is very likely, though. Wiring issues are possible, but less probable. I'd suggest getting a professional diagnosis.

Thanks. Took it to a shop, you were right on the money. They confirmed the transmission control unit was faulty. Replaced it, and all the shifting issues are gone. Cost me about 1000€, like they estimated.

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