Here are a few links I had bookmarked on the subject. Hopefully its helpful. It was more involved than an oil change.
Originally Posted by dnaer
Is there a DIY thread on our transmission fluid change anywhere? I have a little over 80,000 miles and am thinking of just dropping the pan and draining/refilling just to get some fresh fluid in the mix. I do oil, DEF and brakes myself; is this similar or a step above in difficulty/complexity? Thx
2011 335d Sport Package/Cold Weather Package
2004 Ram Cummins with lots-o-mods
1990 YJ Repowered with modified Cummins B3.3T