bad rack and pinion assembly I believe the Chevy Z71 Pickup has a recirculating ball gear box instead of rack and pinion. However, the cause of the problem is still most likely in the gear box.
The problem is probably in the steering gear. Clogged passages in steering gear. Leaks in steering gear.
Low power steering fluid or you need a lube job.
Many things can cause that, the simplest cause being lack of power steering fluid.
A loose or worn belt. Also check the power steering fluid.
probably not the alternator if it happens when only turning its gotta be the power steering or steering rack make sure everything is greased up could be the PS pump going out
The problem is your rack and pinion .
Try checking the power steering fluid. My taurus did the same thing until i filled the power steering fluid.
Turning to the right, when going forward, you turn the steering wheel towards the right.
Might be due to low/no fluid level in the power steering reservoir.
Power Steering Pump
Power Steering pump my have a leak...
If the sound is a loud growling , whining, noise you're probably low on power steering fluid. Now the cause of the fluids loss is WHERE ?