BMW 4 Series Transmission Nightmare: Paddle Shifters Dead

Hey there! I've got some experience with BMWs and had a similar issue with my 2012 BMW 3 series last year. When I read your symptoms, it immediately reminded me of what I went through. My car was also having weird transmission behavior, delayed shifts, grinding, and eventually went into limp mode. After trying a few local shops, I finally found a good mechanic who diagnosed it as a faulty transmission control unit. The repair wasn't cheap, ended up paying about 1000 Euro for the new control unit and programming. But since then, the transmission has been working like a charm. Could you share more details about when these issues started showing up? Like when did you first notice the grinding sounds, and does it happen more during cold starts or after the car's warmed up? This info could help confirm if you're dealing with the same problem I had. And just to be thorough, have you noticed any warning lights on the dashboard?

Thanks for sharing your experience! My car's been pretty well maintained (last service was just two weeks ago at 67273 KM), but these transmission issues started popping up suddenly last week. The grinding noise is actually more noticeable after the car's warmed up, especially when shifting between 2nd and 3rd gear. And yes, I've got the transmission warning light showing up on the dash, along with the reduced power warning. Really stressing about the potential repair costs here. Did your mechanic mention anything about checking the transmission fluid or solenoids before jumping straight to replacing the control unit? Just trying to consider all possible fixes before dropping a grand on this repair. Also, it's good to know yours has been running smoothly since the fix. How long has it been now since your repair? Makes me feel a bit more confident about getting it sorted.

Hey again! Thanks for the follow-up. Yeah, I totally get your concern about the repair costs, been there! Actually, when I had my issue, my mechanic did check the transmission fluid and solenoids first before concluding it was the control unit. The fluid was fine in my case, and the solenoids tested okay too. But I'd definitely recommend getting those checked first, it's way cheaper if it turns out to be just a fluid issue. It's been about 14 months since my repair, and I haven't had a single transmission problem since. My symptoms were really similar to yours, especially that grinding between 2nd and 3rd gear. The warning lights you mentioned are exactly what I saw too. One thing I forgot to mention in my first reply, my mechanic actually found that the control unit had some water damage from a small leak near the transmission. Might be worth checking if there's any sign of moisture around that area in your car. Could save you some diagnostic time. And about the cost, see if your mechanic can source a refurbished control unit. That's what I ended up doing, and it saved me quite a bit compared to a new one. Just make sure they provide a decent warranty on the part. Keep us posted on what you find out! Really curious to know if it turns out to be the same issue.

Thanks so much for that detailed advice! Really appreciate you mentioning the potential water damage, I just checked and actually noticed some moisture around that area. Going to mention this to my mechanic first thing. Definitely going to ask about the refurbished control unit option too; that could be a real money saver. I've booked it in for next week, and they're going to start with checking the fluid and solenoids first, just like you suggested. Feeling much more confident now knowing yours has been running well for over a year after the fix. The symptoms being so similar really helps confirm what might be going on. I'll definitely update the thread once I get it diagnosed and fixed. Thanks again for all your help, it's really made me feel less anxious about the whole situation!