GMC 1994 Yukon Owner's Manual page 83

To release the parking brake:
Hold the regular brake
pedal down. Pull the
lever, located just
above the parking
brake pedal, marked
RELEASE to release
the parking brake.
If the ignition is on when the parking brake is released, the brake system
warning light will go off.
NOTICE:
Driving with the parking brake on can cause your rear brakes to
overheat. You may have to replace them, and you could also
damage other parts of your vehicle.
If you are towing a trailer and are parking on any hill: See "Towing a
Trailer" in the Index. That section shows what to do first to keep the trailer
from moving.
Torque Lock
The parking brake should be set first whenever you leave the driver's seat.
If you are parked on a hill and the transmission is placed in
" P '
(Park)
before the parking brake is set, the weight of the vehicle may put too much
force on the parking pawl in the transmission. It may be difficult to pull the
selector lever out of "P" (Park). This is called "torque lock." To prevent this,
the parking brake should be set BEFORE moving the gear selector to "P"
(Park).
When preparing to move a vehicle parked on a hill, the selector lever should
be moved out of "P" (Park) BEFORE releasing the parking brake. Even
when on level surfaces, its a good idea to set the parking brake first before
shifting the transmission from "P" (Park).
If torque lock does occur, you may have to have another vehicle nudge your
vehicle uphill a little to take some of
the
pressure off the transmission while
you pull the selector lever out of T" (Park).
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