I have a B6100D. I haven't taken mine out yet but the parts manual and the repair manual show it located behind the bolt on the transmission holding the larger hydraulic line in place. It also shows two rubber o-rings for sealing. I mention this because I seem to have bad luck with o-rings, might not hurt to get new ones.
The repair manual dosen't really explain how to remove it so I am assuming you just remove the bolt and pull it out. What kind of oil are you using in the tranny/hydraulic resevoir? A decal on the tractor says to use 80w gear oil, paragraph 90 of the IT shop manual says to use UDT. Searching here looks like I should use the 80w.
I have a pdf version of the parts manual if you'd like a copy.
Rodger