Outer Limits 4x4 Board

I have a 60s power steering box and pump in the zook.When you turn the wheel it makes a loud noise and vibrates through the steering wheel? its not the sound of a slipping belt. So what is the problem the box or the pump?

oil level ok?

no air in the system?

is it only noisy when your wheeling? may be over heating.

i run an auto gear box cooler so it does not over heat. It also somtimes when the engine is switched off the fluid over flows everywhere