Power Steering Issues (maybe the gearbox?)

So I’ve done tried 2 pumps and have been getting screeching before and after they were on. New belt swapped out. Bled it 3 times with about 100x+ of lock to lock. Tightened connections multiple times, but still getting very small amount of bubbles every time that I go and turn the wheel to the right which pushes the oil to the top along with the bubbles. Did a test drive, and it was still hard to turn unless I accelerated with the gas. But from stop or park, it wouldn’t move unless I accelerated hard. It also on wants to turn freely when it’s on stands whether the car was on or off but with a load it screeched like a banshee just from a quarter of a turn and would sometimes stop midway to where it wouldn’t turn and the p/s would stop. I’m trying to figure out if it’s the power steering pump or the gearbox. I checked everything except this and it seems to have the same symptoms except I cannot turn or it’s super hard to. I figured the Buick world would know rather than just assuming. I know gearboxes aren’t cheap either so I want to get it down to the problem so that I can know whether I need to swap it out. I know it’s the original one from 78 and hasn’t been touched.
Any knowledge would help. Thanks.

 

The steering boxes are actually pretty cheap. The Saginaw box was used in brazillians of cars/trucks. Order a reman and go racing.

 

Let's see a picture of the pump + hose connection.

 

I used both the original and new ones which hoses work fine. But I still got the same results both ends.

Thanks for the footnote! I forgot to mention that part lol

I ordered one earlier today. Should be in about a day or 2.

 

Are your pumps remans? It took 2 from Oreillys before I got one that didn't scream. What was wrong with the orig.?

 

Nah I originally had a brand new one installed (engine is brand new with all new parts) and that’s the original one. The second one is a remans. Same results after bleeding and both pumps work fine.