I replaced the fluid in my 06 Mini Cooper as a preventive maintenance measure. There was a slow drip at the drain plug afterward that I didn't correct because I didn't want to go through the drain fill procedure again. Eventually, enough fluid dripped out that the transmission suddenly starting shifting immediately into high range. I drained, refilled and now I still have the problem that arose due to the drip. I had a shop with BMW diagnostic equipment check it out and they found code 001 and code 017.  They also found metal in the trans fluid. The last part worries me, as it was clean when I drained and refilled. I used Redline CVT fluid.