2007 GMC Envoy Owner's Manual - Page 129

Torque Lock If you are parking on a hill and you do not 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) on page 127. 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). Shifting Out of Park (P) Your vehicle has an automatic transmission shift lock control system. You have to fully apply the regular brakes first and then press the shift lever button before you can shift from PARK (P) when the ignition is in RUN. See Automatic Transmission Operation on page 118. 129