Poll: A5S 390R Transmission Fluid & Filter Change

[TiminIndy]

I got my parts and fluid in and plan on doing my transmission fluid & filter change this weekend. I plan to drain and fill twice to get about 75% new fluid in there. I've heard two opinions on this, so I thought I would post a poll.

Should I:

1) Drain and drop the pan / change the filter first, then fill it up, drive it, and drain it again.
(disadvantage to this is that I'm running the 50/50 fluid through the new filter)

2) Drain, fill, drive it, then drain & change the filter and refill.
(disadvantage to this is that there would be more sludge in the sump that the new fluid could stir up into circulation)

My e53 has 96,000 miles and I think it has factory fluid in it. Sure, it might be best to change the filter twice, but I'm not going to bother with that.

[dkl]

3rd option: Drain and drop the pan / change in a "cheap" new filter, then fill it up, drive it, drain it again, drop the pan again and change in you final "preferred" filter and fill it up.

[bcredliner]

BMW states fluid is good for the lifetime of the transmission. Some feel strongly to never change it. Some feel as you do. I change mine every 50,000 miles. At that interval I don't change it twice. I follow the ZF process. https://www.youtube.com/watch?v=S8jcRd4gyWc