BMW 7 Hybrid Transmission Nightmare: Grinding & Gear Problems

Hey there! I have some experience working on BMWs and had a similar issue with my 2019 BMW 5 Series Hybrid (was considering a 7 Series too). Had exactly those symptoms, rough shifts, grinding, wonky gear indicator. Turned out the control unit was shot. Took it to my regular workshop, and they diagnosed it after running a thorough diagnostic scan. The fix wasn't cheap, cost me about 1000 Euro, but it solved the problem completely. They had to replace the transmission control unit and reprogram it. Before sharing more specific advice, could you share: Any warning lights on the dash? When did these symptoms first start? Have you noticed any fluid leaks? Does it happen more when the car is cold or warm? This info would help me suggest if you're dealing with the same issue I had.

Ah yes, I've got similar transmission problems with my 7 Series. I'm at 109171 KM on the clock, and these issues started popping up about a month after my last service. There's a constant check engine light on the dash, and I've noticed the problems are way worse when the car's cold, especially in the morning. No fluid leaks that I can spot though. What's interesting is that my symptoms match yours exactly, the grinding noise is particularly concerning. Did your repair shop mention anything about the hybrid system potentially affecting the transmission behavior? I'm a bit worried since these hybrid transmissions are more complex than standard ones. Thanks for sharing your experience, it's definitely giving me a better idea of what I might be dealing with. The price you mentioned sounds painful, but I guess that's BMW ownership for you!

Hey again! Given your description, I'm even more convinced you're dealing with the same issue I had. My 5 Series started acting up around the 100,000 KM mark too, and that cold-start behavior is exactly what I experienced. The grinding noise drove me nuts, especially during those chilly morning starts. And yeah, the hybrid system definitely complicates things, my mechanic explained that the integration between the electric motor and transmission control unit is super sensitive. When the control unit starts failing, it messes with the hybrid system's power delivery timing. Here's something I didn't mention before, before I got it fixed, I tried resetting the transmission control unit by disconnecting the battery for 30 minutes. It helped temporarily, but the issues came back within a few days. Don't waste your time with that "fix" like I did. After my repair, I've put another 40,000 KM on the car without any transmission problems. Just make sure you go to a shop that really knows their way around BMW hybrids, not all mechanics are up to speed with these systems. Quick tip: get the diagnostic codes read before you go in for repairs. Having that info saved me some diagnostic time (and money) at the shop. The transmission in these cars is generally solid, but when the control unit goes, it really needs proper attention.

Thanks so much for all this detailed info! You've really helped me understand what I'm dealing with. That's super interesting about the battery reset, I was actually considering trying that, so you've saved me some wasted time there! I've got a good BMW specialist in mind, and I'll definitely get those diagnostic codes read before heading in. It's actually a relief to hear that once fixed, you've had no issues for 40,000 KM. Makes the expensive repair seem more worthwhile. The connection between the hybrid system and transmission control unit makes total sense now, I was wondering why the problems seemed worse when switching between electric and gas power. Guess I better start saving up for that repair bill! Really appreciate you taking the time to share your experience. I'll probably book it in next week and get this sorted before it gets any worse. Thanks again for all your help, it's exactly the kind of first-hand experience I was hoping to hear about!