GMC 1995 Safari Owner's Manual page 75

Leaving Your Vehicle With the Engine Running
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 the PARK
(P)
position, 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).
Torque Lock
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 transmission, so
you can pull the shift lever out of PARK (P).
2-23