power steering one way

My 92 f250 has only got power assisted steering when i turn one direction. Does anyone know if this means my steering geared box is no good or if this is going to wreck my steering pump or anything. Also if i do need a new gearbox does it have to be off of an identical model truck or is it the same on a f150 or any others?

its your pump thats bad

I thought that if it was the pump causing the problem that i would have no power steering either direction? Is it possible that the pump would only assist in one direction?

The GEAR is bad, either the pump works, or it doesn't. It is absolutely IMPOSSIBLE for a pump to cause probpems in only one direction.

its your pump thats bad
sorry I misread your post. it wouldn’t work either way if it was the pump. its more then likely the control valve in the gear box which you would have to replace the whole thing

Thanks alot, i changed the steering gear box and everything is working properly now.