The PTO is pretty striate forward. Drain your transmission remove the pump drive shaft the cable or linkage witch ever it may have. Then remove the six bolts that secure it to the transmission and take it to a good clean work bench. Note how it comes apart and disassemble it. If this makes you nervous mark the pats as to how they go with an engraver and take a few pictures of the disassembly process it is pretty simple. The seals may be lip seals or possibly orings or even quad seals. Take the seals and there mating surfaces to a bearing house and they can get you replacements. Also clean and inspect the bearing to determine if you want to replace them at the same time. Remember to get gaskets for between the transmission and the PTO they will come in different thickness get a couple of each. Carefully reassemble you PTO in the reverse of the disassembly. Now when you reinstall your PTO you will mix and match the different thickness gaskets you got till you get 6 to 12 thou backlash between the PTO gear and the gear that drives it in the transmission.
I hope I didn't make this sound too complicated it's not.
