Roger: I have researched this as far as I can with the resources I have available and have determined that the NP540 is an expensive and poor choice for your application. On the LH side a single gear PTO will require a vertical offset adaptor gear, 093. spacer and stud kit. The adaptor may cost more than a PTO. Also you must consider what rotattion you will need. Single gear units rotate crnk but if you need opposite crnk rotation then you must go to a double gear PTO that cost a lot more and you still require the adaptor, spacer and stud kit. All of them run fairly slow, SG is only 25% od engine speed. Too slow really for a hydraulic pump which likes about 60-70% of engine speed. Also this outfit requires 10 inches of free space to the frame flange so it's a large and heavy unit.

Unfortunately I am unable to find out anything on the Spicer 5831 unit. It's too old so you'll need to go to a good PTO drive dealer like Fleet in CA and hope they have some old books. Got rid of all my old stuff a long time ago. Sorry I am unable to be of more assisitance to you.
Good Luck.

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Dave
Engine & Driveline Moderator

If you can't make seventy by an easy road, don't go. ~~ Mark Twain