2009 Hummer H3T Alpha Owner's Manual - Page 345

Maintenance Schedule Ignition Transmission Lock Check While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position. 6-11 Parking Brake and Automatic Transmission P (Park) Mechanism Check pressure from the regular brake pedal. Do this until the vehicle is held by the parking brake only. • To check the P (Park) { CAUTION When you are doing this check, the vehicle could begin to move. You or others could be injured and property could be damaged. Make sure there is room in front of the vehicle in case it begins to roll. Be ready to apply the regular brake at once should the vehicle begin to move. Park on a fairly steep hill, with the vehicle facing downhill. Keeping your foot on the regular brake, set the parking brake. • For automatic transmission vehicles, the ignition should turn to LOCK/OFF only when the shift lever is in P (Park). The ignition key should come out only in LOCK/OFF. mechanism's holding ability: With the engine running, shift to P (Park). Then release the parking brake followed by the regular brake. Contact your dealer/retailer if service is required. • For manual transmission vehicles, the ignition key should come out only in LOCK/OFF. Contact your dealer/retailer if service is required. Underbody Flushing Service At least every spring, use plain water to flush any corrosive materials from the underbody. Take care to clean thoroughly any areas where mud and other debris can collect. • To check the parking brake's holding ability: With the engine running and transmission in N (Neutral), slowly remove foot