I realize that this is long overdue, but here it is!
Let your car cool for an extended period of time (at least 4 hours depending on the ambient temperature) before starting the process. If the transmission's temperature is too high, an incorrect amount of fluid could be added.
83 22 0 440 214 BMW DCTF-1 (1L)
83 22 2 147 477 BMW DCTF-1 (20L)
Special tools needed
1. Remove the protective cover under the transmission.
2. Drain fluid by removing the plastic plug near the front passenger side of the transmission. Fluid can be extremely HOT!
If your car was just driven, I would suggest waiting a few hours before draining the oil.
3. Once the fluid drain stops, reinstall the plug. Torque to the suggested value listed on the plug.
4. Open the filling hole (red box). Using a fluid pump, add M-DCT oil into the transmission. I added about 3 quarts before fluid started to emerge from the filling hole.
5. Ensure that M-DCT fluid inside the transmission is below 90 deg. F.
Then, close the filling hole.
6. Turn on your engine. In position P, maintain 2000 rpm for about 1 minute.
7. Reopen the filling hole and add additional fluid (about 2 quarts) until fluid starts to leak out from the hole again. This process must be completed while the transmission fluid temperature is below 104 deg. F.
8. Close the filling hole and reinstall any removed panels.