You should read this DIY page...
DIY automatic transmission oil change
http://www.1addicts.com/forums/showthread.php?t=617182
While BMW says the fluids are lifetime, the people whop actually MAKE the trans(ZF) say to change it! every ~45K miles, I believe.
This place has everything you need to service any
ZF trans....
http://www.thectsc.com/index.php?p=c...parent=58&pg=1