GMC 2012 Sierra Series Owner's Manual page 292

9-8 Driving and Operating
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
WARNING
If the vehicle has the two speed
automatic transfer case, shifting
the transfer case to N (Neutral)
can cause your vehicle to roll
even if the transmission is in
P (Park) for an automatic
transmission or any gear position
for a manual transmission. This is
because the N (Neutral) position
on the transfer case overrides the
transmission. You or someone
else could be injured. If leaving
the vehicle, set the parking brake
and shift the transmission to
P (Park) for an automatic
transmission or any gear position
for a manual transmission. Shift
the transfer case to any position
but N (Neutral).
Before driving on a hill, assess the
steepness, traction, and
obstructions. If the terrain ahead
cannot be seen, get out of the
vehicle and walk the hill before
driving further.
When driving on hills:
Use a low gear and keep a firm
grip on the steering wheel.
Maintain a slow speed.
When possible, drive straight up
or down the hill.
Slow down when approaching
the top of the hill.
Use headlamps even during the
day to make the vehicle more
visible.
I n f o r ma t i o n P r o v i d e d b y :
WARNING
Driving to the top of a hill at high
speed can cause an accident.
There could be a drop-off,
embankment, cliff, or even
another vehicle. You could be
seriously injured or killed. As you
near the top of a hill, slow down
and stay alert.
Never go downhill forward or
backward with either the
transmission or transfer case in
N (Neutral). The brakes could
overheat and you could lose
control.