Mini Countryman Automatic Transmission Problems

Sounds familiar. I had similar implausible shifting behavior in my Countryman's automatic gearbox, along with the transmission indicator light. Did you check the battery and charging system? Low voltage can cause all sorts of weird electronic issues in these cars.

Interesting! When you say 'low voltage', are we talking about a dead cell in the battery, or something else? I tested the battery and it seemed ok, but perhaps I need to dig deeper. What exactly was the problem in your case? Also, did you notice any change in the transmission performance before the issues started?

In my case, it turned out to be a combination of a slightly weak battery and a faulty voltage regulator. The Automatic transmission is very sensitive to voltage fluctuations. My mechanic mentioned that low voltage can affect the solenoids and sensors inside the automatic gearbox, leading to erratic shifting. I'd advise getting the charging system thoroughly checked by a workshop before doing anything drastic with the Automatic transmission.

You were spot on! It was indeed undervoltage causing havoc with the automatic transmission. Took it to the shop, they confirmed the automatic transmission oil was worn and a transmission flush was performed, it cost me 240€. Shifts like new now. I really appreciate you sharing your experience; it saved me a lot of unnecessary worry and probably a larger bill down the line!