2010 Chevrolet Suburban 2500 Owner's Manual - Page 174

{ WARNING: It is dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll. Heavy Duty 6-Speed Automatic Transmission Shown (Light Duty Similar) See "Range Selection Mode" later in this section. P (Park): This position locks the rear wheels. It is the best position to use when starting the engine because the vehicle cannot move easily. When parked on a hill, especially when the vehicle has a heavy load, you might notice an increase in the effort to shift out of P (Park). See Torque Lock (Automatic Transmission) under Shifting Into Park on page 3‑49 for more information. Do not leave the 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 the vehicle will not move, even when you are on fairly level ground, always set the parking brake and move the shift lever to P (Park). See Shifting Into Park on page 3‑49. If you are pulling a trailer, see Towing a Trailer on page 5‑50. 3-34