Reviving an old thread as I also have watched a shed load of DIY YouTube videos on servicing the worn rubber components in the ZF transmission and pretty much all of those show a plastic pan and a refill port in the side of the unit.
I have a 2005 3.0d and a metal pan so I was like
Reading this thread, members Wpoll and SlickGt1 are correct.
For metal pans you fill through the actually large hole in the pan.
I've since found official BMW info to confirm.
I hope this helps others.
Cheers
