BMW Z4 Trans Issues: Grinding Sounds & Warning Lights

Hey there! I can relate as I had a similar issue with my 2009 BMW M3. The symptoms you're describing are very close to what I experienced. My transmission was also acting up with rough shifts and scary noises. Took it to my regular workshop and turns out the gearbox oil level was critically low, which triggered those warning lights and limp mode. The fix wasn't too complex, they did a full transmission fluid change and recalibration. Cost me about 365 Euro, but it's been shifting smoothly ever since. Could be something similar in your case, but to help better, could you share: Current mileage? When was the last transmission service? Is the grinding constant or only during specific gear changes? (By the way, I switched from the M3 to a 5-series later on, much easier on maintenance!) Let me know those details and I might be able to offer more specific advice.

Thanks for responding! I'm at 188684 KM and had my last service about 6 months ago, though it wasn't a transmission-specific service. The grinding noise mostly happens when shifting between 2nd and 3rd gear, and it's gotten worse over the past few weeks. I'm hoping it's just low fluid like in your case, that would be a relief compared to a full transmission replacement! Did you notice any particular symptoms before the fluid change that might help me compare? I'll definitely get it checked out by a mechanic this week, but it's good to know what they should be looking for. Thanks for offering to help. These transmission issues can be pretty stressful!

Hey again! Yeah, those symptoms definitely sound familiar, my M3 was doing almost the exact same thing around 175K KM. Before I got the fluid changed, I noticed the grinding was also worst between 2nd and 3rd gear. It started as a subtle harsh shift and got progressively worse over about a month. But here's something interesting, before taking it to the workshop, I was also convinced it was the transmission pressure sensor (like you mentioned in your first post). The symptoms can be really similar. However, in my case, after they did the fluid change and recalibration, they found that some metal particles in the old fluid had actually started to affect the sensor readings, making the computer think there was a sensor issue when it was really just dirty, low fluid causing the problems. Since your last service wasn't transmission-specific, and you're at 188K KM, I'd definitely recommend having them start with a fluid check and change. If you're getting the same grinding I had, there's a good chance that's your issue. Just make sure they use the correct BMW transmission fluid, that's super important. Keep me posted on what you find out! Always happy to help another BMW owner avoid the stress I went through.

Thanks so much for the detailed explanation! That's actually really reassuring to hear that you had such a similar experience. I just called my mechanic and scheduled an appointment for tomorrow morning. I specifically mentioned the transmission fluid check and change, and made sure to ask about using the proper BMW fluid. You've definitely helped calm my nerves about this, I was imagining much worse scenarios! It makes total sense about the metal particles affecting the sensor readings too. I'll make sure they check for that during the service. Really appreciate you taking the time to share your experience and knowledge. I'll update you once I get it checked out, but feeling much more optimistic now that it might just need a good fluid change rather than anything more serious. Thanks again for all the help!