I was starting to have what felt like jerky/rough shifts in my Bimmer, so I read up on how to change the fluid (easier and less costly than a ZF-equipped unit!). When I dropped the pan, there was a [censored] of metal in the bottom of the pan and the magnet was pretty well coated. I also changed out the filter, but did not cut open the filter. There was still some red in the fluid, but was pretty dark which was to be expected. After changing the fluid, the shifts have been a bit smoother.