2005 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 112

Automatic Transmission Operation If your vehicle is equipped with an automatic transmission, it features an electronic shift position indicator within the instrument panel cluster. This display must be powered anytime the shift lever is capable of being moved out of PARK (P). See Fuses and Circuit Breakers on page 5-128. There are several different positions for your shift lever. PARK (P): This position locks your rear wheels. It is the best position to use when you start your engine because your vehicle cannot move easily. If your vehicle is equipped with the Allison Transmission®, use PARK (P) for stationary operation of the Power Takeoff (PTO), if equipped. The Allison Transmission® is equipped with park pawl designed to hold the higher weight of commercial medium duty trucks. Therefore, the Allison Transmission® uses larger parts than other automatic transmission. These larger parts may sometimes make a clunk noise when the selector lever is moved from DRIVE (D) or REVERSE (R) to PARK (P). This is normal and there is no damage occurring during these shifts. {CAUTION: It is dangerous to get out of your vehicle if the shift lever is not fully in PARK (P) with the parking brake firmly set. Your vehicle can roll. Do not leave your vehicle when the engine is running unless you have to. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. To be sure your vehicle will not move, even when you are on fairly level ground, always set your parking brake and move the shift lever to PARK (P). See Shifting Into Park (P) (Automatic Transmission) on page 2-50. If you are pulling a trailer, see Towing a Trailer on page 4-69. 2-26