Noise When Started And Turning

[SkyWalker209]

94 Chevy 1500 w/ V6

 

When I start my truck (hot or cold) occasionally I'll here a noise up front. When I turn my wheels, it gets louder. I've replaced the power steering pump thinking that would resolve the issue. Well, it didn't. Whats got me baffled is it happens intermittently. I can drive it for an hour and start it up 5 minutes later and it CAN happen or I can get in it in the morning and it CAN do it. Keyword being CAN. Sometimes it happens, sometimes it doesn't. It's not a grinding or squealing noise. Almost like a knock or a pump running out of fluid. (Yes, I checked the power steering fluid and it's right where it should be). Any ideas of what it may be?