2004 GMC Yukon Owner's Manual - Page 418

Power Steering Fluid All Other Engines 8100 Engines 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 5-14 for reservoir location. 5-40