Electric Auto/Apply System Bleeding
WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 1999 Pontiac Montana, 1999 Oldsmobile Silhouette, 1999 Oldsmobile Bravada, 1999 GMC Yukon, and 1999 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.
Check fluid level with engine off and transmission in Park. Fluid level should be up to the FULL mark on reservoir. Fill reservoir with Dexron III ATF, as necessary.