Transmission problems in 2005 GLK Diesel: experience and tips wanted

Hi mate, sounds like you had a similar scare to me with my 2008 E-Class diesel. On my Benz the symptoms were almost identical, and ultimately the transmission control unit was faulty. Funnily enough, my first guess was also the gearbox oil or sensor, but that wasn't it. It was a pretty big deal, because the car is almost impossible to drive without a functioning transmission control unit. What's more, replacing and reprogramming it was a tricky job that I preferred to leave to the professionals. So if you notice that your GLK is showing the same symptoms, save yourself the headache and let the experts get to work. It's a bit silly to have such problems with your car. Hopefully it's not that extreme in your case. Good luck, buddy!

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Hey, thanks for your quick reply! It sounds like you've been in the same shoes I'm in right now. That's not exactly reassuring, to be honest. I suppose whenever gear is involved, it usually doesn't mean anything good - or cheap. Can you remember how much you had to pay in total for the repair? And have any other problems cropped up since the replacement or was the transmission control unit the only culprit? Best regards and thank you in advance!

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Hey, yes, it seems we've faced the same problems! All too true that transmission problems in cars are rarely a pleasant or cheap affair. I paid a whopping €1000 in total for the repair, with the faulty transmission control unit going on the lift. It was a considerable chunk of money, but what are you going to do? Since then, the old car has been running like a charm again. This transmission oil temperature sensor, which I suspected, also played a part in this. After replacing the control unit at the mechanic's, the problem with the malfunctioning sensor was also resolved. So, the transmission control unit was obviously the main culprit. I hope that it won't be so expensive for you and that everything will be up and running again quickly. Good luck with that! Best regards!

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Hello again, thank you very much for the detailed reply. It looks like I'm in for a more expensive repair than I originally thought. But it's good to know that your Benz hasn't had any further problems after replacing the transmission control unit. Despite everything, my GLK-Class is a good car and has never let me down. So I'm going to call in the experts and hope that everything gets fixed quickly. As soon as there is any news, I will keep you up to date. Thanks again for your help and advice! See you soon, guys!

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No, due to illness I was unable to solve the problem. I have canceled an appointment with Mercedes.

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However, I was able to clear the check engine light again because Carly ran an update.

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These are non-critical errors that may come back.

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According to Carly, it's a non-critical fault that I can always clear. Maybe I'll go to a service partner soon who can do a gearbox flush.

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Consider checking the transmission fluid level and condition first, as low or dirty fluid can cause slipping and grinding. If the fluid is low, top it up and see if the issue persists. If it's dirty, a flush might indeed help. Keep us updated on your progress, and feel free to ask if you have more questions!

Please ensure that the transmission fluid is at the correct level and in good condition. If the fluid is low, top it up and monitor if the issue continues. If the fluid appears dirty, a transmission flush could be beneficial. Let us know how it goes, and reach out if you have further questions!