Great post Edward! Enjoying all that work - from a distance!
Must be a number of dairy cows in your neighborhood. That's quite a "poop pile" you're movin' onto the fields!
That "mystery filter"... well, there's really only 4 things that get filtered on a tractor - fuel, oil, hydraulic fluid and air. Don't believe it's air..

and it not likely fuel given the size of the inlet and outlet lines - 'course you might have a 13.6 liter in that 5085, huh?
So, that leaves oil and hyd fluid. Finally, realized that the pic is orientated wrong... and the filter is really parallel to the ground and located at the rear of the tractor - it's a hyd filter!
Sure like the looks of your 5085M. Does make me wonder a bit if I should have gone up another step to the 85? Oh well, that horse it outta the barn, now!
Thanks again for a look at your farm and the work you're doing this Spring. Appreciate you taking the time to "fool with a camera" in the field and then loading everything on TBN. :thumbsup:
AKfish