2001 Dodge Dakota - Power steering issues

I have a 01 dodge Dakota 4.7l and my power steering is driving me crazy. It started whining when I would turn so I replaced the pump and bled it correctly. Still whines. 1 year later and 3 brand new, not remanufactured, pumps later and I finally change the rack and pinion. Still whines.
I don’t think the high and low pressure hose are bad because fluid can pass through them and it doesn’t leak from what I can tell.
I want to sell this truck for a bigger one for my lawn care business.
I will take ANY advice you can give me…. Thanks.

did you replace the P/S reservoir? if I remember correctly, it has a screen built in that gets gummed up and can cause your problem.