GMC 1997 Safari Owner's Manual page 370

Ignition Transmission Lock Check
While parked, and with the parking brake set, try
to turn
the ignition key to LOCK in each shift lever position.
I
a The key should turn to LOCK only when the shift
lever is in PARK
(P).
The key should come out only in LOCK.
Parking Brake and Automatic Transmission
PARE-
-P)
Mechanism Check
I
Park on a fairly steep hill, with the vehicle facing
downhill. Keeping your foot on the regular brake,
set the parking brake.
0
To check the parking brake's holding ability:
With the engine running and transmission in
NEUTRAL (N), slowly remove foot pressure from
the regular brake pedal. Do this until the vehicle is
held by the parking brake only.
a To check the PARK
(P)
mechanism's holding ability:
With the engine running, shift to PARK (P). Then
release all brakes.
When you are doing this check, your vehicle
could begin to move. You or others could be
injured and property could be damaged. Make
sure there is room in front of your vehicle in case
it begins to roll. Be ready to apply the regular
brake at once should the vehicle begin to move.
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