GMC 1999 Sierra 1500 Pickup Owner's Manual page 229

AM470053
If there is no curb when you're parking uphill, turn the wheels to the right.
If there is no curb when you're parking uphill on the left side of a one-way
street, your wheels should be turned to the left.
Torque Lock (Automatic Transmission)
If you are parking on a hill and you don't shift your transmission into P
(Park) 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 P (Park). This is called "torque lock." To prevent torque lock, always
be sure to shift into P (Park) before you leave the driver's seat. To find out
how, see "Shifting Into P (Park)" in the Index.
When you are ready to drive, move the shift lever out
of P (Park) 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 P (Park).
4-5
1