BMW Auto Trans Failure: What to Expect & Where to Go

Had the exact same symptoms on my 2007 BMW 3 Series 320d last summer. The transmission control unit was completely shot in my case. Started with irregular shifting patterns and grinding noises, just like yours. The warning lights came on soon after. Got it diagnosed at a BMW specialist garage. The mechanic found the transmission control unit was defective and needed replacement. It was quite a serious issue that required specialized programming after installing the new unit. Took them about 3 days to complete the whole job. The shifting has been perfect since the repair, no more warning lights or strange noises. Would definitely recommend finding a proper BMW specialist rather than a general mechanic for this kind of work. Given your symptoms, it sounds very similar to what I experienced.

Thanks for sharing your experience, it really sounds identical to what I'm dealing with now! Since you had this fixed last summer, mind if I ask how much the transmission control unit replacement set you back? Also curious if you've had any other transmission problems since the repair? Trying to get an idea of what I'm in for cost-wise and if this fix tends to last.

Hey there! Happy to give you an update on my 320d transmission repair. I ended up paying 1000 € for the whole job, including the new control unit and programming. The mechanic really knew what they were doing, and I'm glad to report the gear shift indicator problem is completely sorted now. The display works perfectly, and all those annoying warning lights are gone. Since getting it fixed last summer, I haven't had a single problem with the transmission, it shifts like a dream! Honestly, it feels better than before the issues started. No more grinding noises or unusual gear changes. It was worth every penny to get it properly sorted by a specialist. Just make sure you find a good BMW specialist who knows what they're doing with these transmissions. The programming part after installing the new control unit is really crucial. Would definitely say go for it, it's not a cheap fix, but it's way better than risking more damage to the transmission.

Thanks so much for all those details! I bit the bullet and took it to a BMW specialist yesterday. Turns out you were spot on, it was the transmission control unit. Apparently water had gotten in there somehow and fried the circuits. Cost me about 1200 € in total, a bit more than yours but they also found and fixed a small oil leak while they were at it. The mechanic was great, really took the time to explain everything and even showed me the damaged parts. They had it done in two days, and wow, what a difference! The transmission's shifting perfectly now, no more weird noises or warning lights. The dash display is working properly again too. Really glad I asked here first, saved me from taking it to another dodgy mechanic who probably would've just made things worse. The car feels like new, honestly better than it has in years. Definitely worth the investment!