Need help identifying steering pumps

[NikFu S.]

So I have two steering pumps, both old and very used, one was momentarily operating without fluid (though functioned fine afterward) and the other sat in a junkyard for who knows how long so they are both possibly damaged, but I can't confirm that since neither of them made this horrible noise until after my mech tore my engine down. That's problem one. problem two is I don't trust the scrapyard to label SVX parts correctly so really have no idea if I bought the right model. Problem 3, the mech mix and matched "the best" parts between the two and it's still making this awful sound, and my steering is obviously not working despite having a brand new rack assembly which worked perfectly (along with my original steering pump) after I installed it.

I find it suspicious that both pumps would have bad bearings after the tear down so I am wondering if it is not being powered correctly or something.

How do I tell the difference between the two steering pump models?

Are there any other causes for a terrible whining sound coupled with unassisted steering?

[92snowmachine]

If the o ring under the reservoir is bad it will whine and have no assist if the fluid is aerated. As far as I know all the svx pumps are the same.

[NikFu S.]

Possibly, but I do show 2 different model numbers, each uniquely assigned to either speed sensitive (34411PA001) or electronic (34411PA071) steering modes.

Frankly I'm even more baffled by this as I thought the electronically controlled version was speed sensitive and the lower trim used RPM sensitive.

[92snowmachine]

from all the info i can find the only difference i can find is that the engine speed sensitive pump has a relief valve internal to the pump which should be just before the pressure line leaves the pump. the vehicle speed sensitive pump doesn't show this part in the exploded views and it says the relief valve is located on the top of the rack and is controlled by computer. if one pump has a larger housing where the pressure line connects it is probably the engine speed pump.

you could remove the fitting and find out but i'm not positive this is the only difference.