Changed my lady friends X3 transfer case which by the way is WAY more important to change periodically than the transmission and also the transmission fluid and filter.
Transfer case had 63K and I wish I had done it at 50K but oh well. It was very black and holds only 0.6L of BMW fluid. Easy to change. Drained and dropped the pan, cleaned the magnets and replaced the filter and reinstalled, pumped ESSO Lt 71411 which is the same thing as Lifeguard5 spec'ed for this transmission. I believe around 5L. Transmission warm to temp added another 3/4L. Job done.
Only issue is using a inch pound torque wrench since the values are so low. By the way the Lifeguard5 I drained out was Coke colored and smelled bad however Esso smells bad anyway so I didn't think it was actually shot. I will do this in another 30-40K miles and for sure 30K miles for the transfer case since it is where all the power is sent from the engine and just too important and contains such a small amount of fluid to not change it often.
I didn't have guts enough to stray away from the OEM like using Redline or other fluids...