1999 GMC Sonoma Owner's Manual - Page 87

yellowblue If you have to leave your vehicle with the engine running, be sure your vehicle is in PARK (P) and your parking brake is firmly set before you leave it. After you've moved the shift lever into PARK (P), hold the regular brake pedal down. Then, see if you can move the shift lever away from PARK (P) without first pulling it toward you. If you can, it means that the shift lever wasn't fully locked into PARK (P). Shifting Out of PARK (P) (Automatic Transmission Only) CAUTION: Before shifting out of PARK (P) you must fully apply your regular brakes. Your vehicle can roll. If you have left the engine running, the vehicle can move suddenly. You or others could be injured. If you're pulling a trailer, see "Towing a Trailer" in the Index. Your vehicle has a Brake-Transmission Shift Interlock (BTSI). You have to fully apply your regular brake before you can shift from PARK (P) when the ignition is in RUN. See "Automatic Transmission Operation" in the Index. If you cannot shift out of PARK (P), ease pressure on the shift lever -- push the shift lever all the way into PARK (P) as you maintain brake application. Then move the shift lever into the gear you want. Torque Lock (Automatic Transmission) If you are parking on a hill and you don't shift your transmission into PARK (P) properly, the weight of the vehicle may put too much force on the parking pawl in the transmission. You may find it difficult to pull the shift lever out of PARK (P). This is called "torque lock." To prevent torque lock, set the parking brake and then shift into PARK (P) properly before you leave the driver's seat. To find out how, see "Shifting Into PARK (P)" in the Index. When you are ready to drive, move the shift lever out of PARK (P) before you release the parking brake. If torque lock does occur, you may need to have another vehicle push yours a little uphill to take some of the pressure from the parking pawl in the transmission, so you can pull the shift lever out of PARK (P). 2-29