New power steering pump STILL whining

2000 XJ 4.0

My power steering pump was whining pretty loud and it felt like it was getting weak so I upgraded it with a pump from a WJ with a hydraulic fan clutch.

When I did the upgrade I was surprised at the lack of difference I felt. A year or so prior to replacing the power steering pump, I upgraded to a faster s-10 power steering box. For a while it was fine but now my steering feels all kinds of sloppy. I attributed it to being used to driving my new Lincoln LS, but now I'm thinking it's abnormally sloppy, especially considering the "upgraded" power steering box.

But what baffles me is why my "new" power steering pump is whining. I realize that it was a junkyard upgrade and there's definitely the possibility of getting a bad pump but the junkyard verified that it was in working order and the WJ that it came from only had ~70k miles. Besides that, when I first did the swap, the power steering pump was quiet but now it's whining similar to (but not quite as loud as) the old pump.

Therefore I'm thinking the problem must somehow lie in the box and that somehow it's making the pump whine. But I don't know all that much about power steering boxes so any help would be greatly appreciated.

It's probably pulling air into the system from somewhere. Do you have any wet spots? If fluid is seeping out under load one direction it is probably pulling air in when you turn the wheel to the other direction

A plugged up steering box could make the pump whine due to the pressure not being able to go anywhere. if your steering is sloppy I would start there. take the drag link TRE off the pitman arm and see if you can move the pitman at all with your hand, you shouldn't be able to move it with your bare hand, any play would be multiplied by the power steering system by the time it got up to the wheel. also, with the drag link connected and the truck off you shouldn't be able to turn the wheel more than an inch or so before it starts trying to move the tires.

As far as the box having a blockage in it I don't know of a good way to test it or clear a blockage, but I know they do get clogged up from time to time.