when I had my MM hydro winch, I seem to recall coming across numbers that were like around 1000psi @ 2GPM.. but thats very old unverified data, so take it how you like.

but yes, I have been mostly unhappy with my hydro assist setup which relies on the stock pump and box. my personal opinion is the box is more a limitation than the pump, but again, thats only an opinion. I've got several friends who have hydro assist setups on various other vehicles and my setup isn't half of what a good hydro assist setup feels like/handles.

if you're thinking hydro assist with the stock isuzu stuff, my advice would be put the time/energy into swapping in different and more common components.

-Rob