Power Steering Diagnosis

[Zulu Kono]

'97 Tahoe.
Power steering fluid has been leaking for weeks and I've just
been topping it off because I haven't had time to address it.
Thought it was low on fluid again because it was super hard to turn the wheel.
When I poured fluid in the reservoir, it immediately started overflowing.
So I drove it around the block and the power steering worked fine as long as I
was up to speed, but at slow speed or stopped there is no power steering at all.
Is the pump shot?
Do I have a bad hose?
Something else?
Thanks in advance.

 

[GoToGuy]

Could have air, very good chance run to low on fluid and damaged pump, that could be why it only makes pressure in higher RPM, I would test further confirm.

 

[Schurkey]

Could be the pump. Could be the steering gear. Might be a restricted hose.

This thing have Hydroboost?

Find and fix the leak. See what happens. MAYBE you can get a PS pressure gauge from the loaner-tool section of a local parts store.