Power steering pump or rack?

[JohnAE82]

My power steering is acting up ('85 sedan). When I turn the wheel, the steering wheel shakes and jerks in my hand, and pulls down on the engine to the point of almost stalling it out. It’s not as noticeable when moving, but is really noticeable when still or slowly moving. It is using PS fluid, but I can’t tell where it is leaking at (there is 25 y/o grime over everything).
What could be malfunctioning, the pump or the rack?

[4agetercel]

i would say the pump