I have a 88xj 4.0 project vehicle. we have the stock power steering unit and steering box. when we got the vehicle the powersteering fluid was empty. I have added fluid. and primed the pump by turning the wheels lock to lock until it stopped taking fluid.
when I put the power steering cap...
I'm running BFG mud terrains and they are awsome. I deal with a lot of snow and mud and they work magic i have never gotten stuck. I loose a little bit of power and it burns a little more gas but not a very big difference.