The stock filler plug on all Vanagon manual trannys is a sometimes PITA
17mm allen head. I have found a replacement filler plug that uses a hex
17mm wrench, like any ordinary bolt. This filler plug lets you access
the filler hole more easily since a simple open end wrench fits up in
there without any interference with the shift linkage. This filler plug
is a BMW part. It costs about $4, or at least it did last week. If you
own one of the new "gear wrench" type tools in 17mm you will really like
this new plug. I have purchased the same basic plug under 2 different
BMW numbers.

BMW part#  23117 527 440

also  superseded  by:
BMW part# 23117 510 100

These plugs are not suitable as drain plugs since they don't have the
magnet that the VW drain plug has.

Mark