I am running an fj60 gear box with saginaw pump with hydro assist and it works great running 38.5 tsl/xs. With hydro assist it WILL turn with arb locked, but its not happy about it.
Mini truck stuff works decent up to 33's. Do it once and be done. Its not fun to have your ability to run bigger tires limited by your power steering set up that you recently installed. Ask me how i know