My X5 xDrive 35d is now having the same issue of "Transmission Malfunction" described by so many others. The error message adds;
"Drive moderately. Continued driving possible. Reduced acceleration. Have the system checked by nearest BMW dealer."
First time it happened set me back $2000, but then it occurred again just a week later after the "repair". It occurred once while trying to pass a truck on a two lane highway in the mountains, nearly causing an accident for me and the driver behind me also trying to pass.
The second time they said it needed a quart of transmission fluid, everything else looked fine, and after all, there was no error message logged in the computer. In addition, they noted stopping and re-starting the car, always sets in back to normal.
It's happened several other times now, all on the highway when modest acceleration is required. I have been a big fan of BMW, but I believe this problem is
truly a dangerous one, I'm dismayed and disappointed by the BMW dealer response to it, and my faith in the BMW brand is going.