Mercedes B Klasse gear shift indicator issue

Sounds nasty. I had a similar issue with my old Audi A6. The symptoms you describe, especially the slipping and the gear selector display going blank, are very indicative of a faulty control unit. The transmission control unit (TCU) is responsible for managing the gear shifts and displaying the current gear. If it's failing, it can cause all sorts of weirdness. Do you have access to a diagnostic tool to read the specific error code stored in the memory? That would help to pinpoint the issue.

Thanks for the quick reply! I've got a basic OBD2 scanner. It's throwing a code related to the gear selector signal being implausible. What's weird is the shift knob itself seems fine, it's just the digital display in the instrument panel that's not working. Could that still be the TCU or something else?

The 'implausible signal' code definitely points toward a problem with the communication between the gear selector, the TCU, and the instrument panel. Since the shift knob feels okay, the issue is likely not the shift knob mechanism itself. Given that the digital display is blank and the transmission is behaving erratically, I'd still suspect the TCU or potentially a wiring harness issue between the TCU and the instrument panel. However, without more advanced diagnostic equipment (like a Mercedes-specific scanner), it's difficult to say for sure. My advice would be to take it to a reputable workshop with experience in Mercedes transmissions. They'll be able to run more detailed diagnostics and pinpoint the exact cause. Be prepared for a potential control unit replacement, as that was the culprit in my case. I'm afraid it won't be cheap.

Thanks a million for the advice. I took it to a Mercedes specialist and you were spot on. They confirmed the TCU was defective. Cost me around 1000€ to replace, but at least it's fixed. Appreciate the help!