Chevrolet 2003 Silverado 1500 Pickup Owner's Manual page 420

How to Check Power Steering Fluid
Turn the key off, let the engine compartment cool down,
wipe the cap and the top of the reservoir clean, then
unscrew the cap and wipe the dipstick with a clean rag.
Replace
the cap and conipletely tighten it. Then remove
the cap again and look at the fluid level on the dipstick.
The level should be at the FULL COLD mark. If
necessary, add only enough fluid to bring the level up to
the mark.
All Other Engines
What to Use
To determine what kind of fluid to use, see Part D;
Recommended Fluids and Lubricants on page 6-78.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering fluid
unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired. See Engine Compartment Overview
on page 5-72 for reservoir location.
Always use the proper fluid. Failure to use the proper
fluid can cause leaks and damage hoses and seals.
5-45