100% Free

No Scanner Needed

Carly logo
Prices

HondaFabi

BMW 8 Series Transmission Nightmare: Warning Lights & Noise

Hey all! Having some serious concerns with my 2021 BMW 8 (99k km). The transmission's acting up, jerky shifts, grinding sounds, and both engine and transmission warning lights are flashing. The car's gone into some kind of emergency mode. I suspect it might be the transmission temp sensor, but after a previous sketchy experience with a mechanic, I'm hesitant about where to take it. Has anyone dealt with similar symptoms? What was the actual problem and how much did the repair cost? Thanks in advance for any input! -Mark

Summary of the thread

A 2021 BMW 8 Series owner experienced transmission issues, including jerky shifts, grinding noises, and warning lights, leading to an emergency mode activation. The suspected cause was a faulty transmission temperature sensor. Another individual with a similar problem suggested that low gearbox oil, due to a leak, might be the issue, recommending a certified BMW specialist for accurate diagnosis and repair. The solution involved replacing the gasket, refilling the transmission fluid, and resetting the control module, which resolved the problem and restored smooth operation.

Did this summary help you solve your problem?

4 comment(s)

EugenM4n1ac

Hi! I had a similar situation with my 2018 BMW M5 last year. The symptoms you're describing match exactly what I experienced, rough shifting, grinding, and warning lights. Initially, I also thought it was just a sensor issue. Turned out the gearbox oil level was critically low, causing overheating and those jerky shifts. The transmission was going into limp mode to prevent damage. In my case, there was a small leak at the transmission pan gasket that had been slowly dripping. The fix wasn't overly complex, they replaced the gasket, refilled with the correct BMW transmission fluid, and reset the transmission control module. Definitely get it checked soon though, running low on transmission fluid can cause serious damage if left unchecked. Look for a certified BMW specialist rather than a general mechanic. The diagnostic equipment needs to be brand-specific for accurate readings. Hope this helps.

HondaFabi (community.author)

Thanks for sharing your experience, that's incredibly helpful as it seems we had identical issues! Was actually worried it might be something way more serious. I'll definitely check out a certified specialist like you suggested. Would you mind telling me roughly how much you ended up paying for the whole repair job? Also, has everything been running smoothly since then, or have you noticed any other transmission-related problems?

EugenM4n1ac

Great to hear back from you! Since your last message, I actually took my M5 to the certified BMW specialist I mentioned. Just got it back last week, turned out I was spot on about it being a faulty transmission oil temperature sensor. They also found the gearbox oil level was running low, just like I had. The total bill came to 365 € for parts and labor, which wasn't as bad as I initially feared. Since the repair, the car's been shifting like a dream, no more jerky movements or warning lights. Those grinding noises I mentioned? Completely gone. Looking back, I'm really glad I didn't wait any longer to get it fixed. The transmission's now working exactly how it should in a car of this caliber. I've put about 1,000 km on it since the repair with zero issues. If you're still looking for a reliable place to take yours, I'm happy to share more details about my experience with the specialist. They really knew their stuff when it came to these specific transmission problems. Let me know how you get on with yours!

HondaFabi (community.author)

Just wanted to update you on my situation. Finally got my car back from the shop yesterday! You were right about going to a certified specialist, they diagnosed the issue right away. The mechanic found a similar problem to yours, low transmission fluid and a failing sensor. Got it all sorted out for around 400 €, which was actually better than I expected. They even did a full system check while they had it, which gave me some extra peace of mind. The car's running beautifully now, no more warning lights or weird noises. Feels like I'm driving a new car again! Should've done this weeks ago instead of worrying about it. Really appreciate your help with this. You saved me from potentially making the problem worse by putting it off. Thanks again for sharing your experience, it definitely helped me make the right call.

rmh_community_comment_box_header

community_crosslink_scanner_headline

community_crosslink_scanner_intro

community_crosslink_scanner_title

community_crosslink_scanner_price

community_crosslink_rmh_headline

community_crosslink_rmh_intro

community_crosslink_rmh_title

community_crosslink_rmh_subtitle

community_crosslink_rmh_brand

BMW

community_crosslink_rmh_model

8