BMW Z4 Transmission Nightmare: Grinding Gears & Limp Mode

I had the exact same symptoms on my 2010 BMW Z4 sDrive35i last year. After the transmission light and check engine came on, the car went into limp mode and barely moved. Harsh shifting and that grinding noise were definitely there too. Turned out it was indeed the torque converter that was failing. Got it diagnosed at my local BMW specialist, the lock-up clutch was completely worn out inside the converter. Had to get the entire torque converter replaced since these units can't be repaired separately. It was quite a serious job that took about 4 days at the shop since they had to drop the transmission to replace the converter. Mine was also showing metal particles in the transmission fluid, so they had to flush the whole system thoroughly. From what the mechanic told me, this is a known weak point on these transmissions when they get higher mileage. Since getting it fixed, the transmission has been shifting perfectly smooth, and all the warning lights are gone. It was worth fixing rather than risking more damage.

Thanks for sharing your experience! It definitely sounds like I'm dealing with the same issue on my Z4. Really helpful to know what to expect. Quick question, do you remember roughly how much you ended up paying for the whole repair? And has everything been running smoothly since, or have you noticed any other transmission quirks popping up?

Hey there! Really glad I could help with my previous reply. About the cost, I ended up paying 2120 € to get the torque converter lock-up clutch fixed. I know it wasn't cheap, but it was totally worth it. And great news, since getting it sorted, my Z4's transmission has been working like an absolute dream! No more grinding noises, harsh shifts, or warning lights. It's been shifting super smoothly through all the gears, just like when the car was new. Zero transmission issues have popped up since the repair, and it's been such a relief. I can actually enjoy driving my Z4 properly again now, no more worrying about getting stuck in limp mode or dealing with those annoying transmission warnings. If you're experiencing the same symptoms, I'd definitely recommend getting it fixed before it potentially causes more damage. The peace of mind alone was worth the investment for me!

Thanks so much for all the details! Really appreciate you sharing the repair cost too, helps me know what I'm looking at budget-wise. While it's not exactly cheap, it's better than having to replace the whole transmission or being stuck with a car I can't properly drive. Just got back from my mechanic actually. You were spot on, it's definitely the torque converter. They quoted me pretty similar to what you paid. Had to leave my car there but they said it should be ready by the end of the week. The mechanic seemed really knowledgeable and even showed me what was causing the issue. Way better experience than my last repair shop! Fingers crossed it'll run as smoothly as yours after the fix. Can't wait to get back to properly enjoying my Z4 again without all these transmission headaches. Thanks again for all your help, it really made me feel more confident about getting this sorted!