FLUID RECOMMENDATIONS AND LEVEL CHECKS
Power steering fluid level should be checked at least once every 7,500 miles. Low fluid level usually causes a moaning sound as the wheels are turned (especially when standing still or parking) and increases steering wheel effort.
To prevent possible overfilling, check the fluid level only when the fluid has warmed to operating temperatures and the wheels are turned straight ahead (unloading the pump). If the level is low, fill the pump reservoir with suitable fluid until the fluid level measures full on the reservoir dipstick. Be sure to ONLY use GM power steering fluid, or equivalent.