Joey-D

I just purchased a 1999 chevy venture 3.4 with 154K on it. It has no power steering at all. The previous owner say it has been out for a while. The reservoir was very low on fluid. I topped it off, cycled the wheels left to right a few times. It gulped up some fluid, but never a hint of "power" steering. Took it for a ride and still nothing. No obvious leaks. Simple system, pump, high pressure line, rack, return line. This is the odd part, the pump never whined. Low on fluid or full of fluid. The fluid did have small bubbles when I added it. So what is shot, the rack or the pump or both? Don't want to just randomly start replacing parts.