Thanks for all the info. My trans is a Hurth 450, but it looks just like the manual you provided. And yep, I can see (barely) where the filter is undernearth the trans, just where manual says.
So....can it actually be taken out without removing the trans? There appears to be only a few inches clearance between the cover and bottom of boat. And, I can't even see one of the bolts. Can feel it though. I'm not even sure I could get the bolts backed out enough.
Any words of wisdom are appreciated.