Black plate (7,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - CRC - 6/6/14
Driving and Operating 9-7
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower
air dam.
{Caution
Operating the vehicle for
extended periods without the front
fascia lower air dam installed can
cause improper air flow to the
engine. Re-attach the front fascia
air dam after off-road driving.
Loading the Vehicle for
Off-Road Driving
{Warning
.Unsecured cargo on the load
floor can be tossed about
when driving over rough
terrain. You or your
passengers can be struck by
flying objects. Secure the
cargo properly.(Continued)
Warning (Continued)
.Keep cargo in the cargo area
as far forward and as low as
possible. The heaviest things
should be on the floor,
forward of the rear axle.
.Heavy loads on the roof raise
the vehicle's center of gravity,
making it more likely to roll
over. You can be seriously or
fatally injured if the vehicle
rolls over. Put heavy loads
inside the cargo area, not on
the roof.
For more information about loading
the vehicle, see If the Vehicle Is
Stuck on page 9-14 andTires on
page 10-51.
Environmental Concerns
.Always use established trails,
roads, and areas that have been
set aside for public off-road
recreational driving and obey all
posted regulations.
.Do not damage shrubs, flowers,
trees, or grasses or disturb
wildlife.
.Do not park over things that
burn. See Parking over Things
That Burn on page 9-32.
Driving on Hills
Driving safely on hills requires good
judgment and an understanding of
what the vehicle can and cannot do.
{Warning
Many hills are simply too steep
for any vehicle. Driving up hills
can cause the vehicle to stall.
Driving down hills can cause loss
of control. Driving across hills can
cause a rollover. You could be
injured or killed. Do not drive on
steep hills.
Before driving on a hill, assess
the steepness, traction, and
obstructions. If the terrain ahead
Black plate (91,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - CRC - 6/6/14
Driving and Operating 9-91
forward that it will contact the back
of the cab in sharp turns. This is
especially important for short box
pickups. Trailer pin box extensions
and sliding fifth-wheel hitch
assemblies can help this condition.
There should be at least 15 cm (6 in)
of clearance between the top of the
pickup box and the bottom of the
trailer shelf that extends over
the box.
Make sure the hitch is attached to
the tow vehicle frame rails. Do not
use the pickup box for support.
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue of
the trailer to help prevent the tongue
from contacting the road if it
becomes separated from the hitch.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer. If the trailer being
towed weighs up to 2 271 kg
(5,000 lb) with a factory-installedstep bumper, safety chains may be
attached to the attaching points on
the bumper; otherwise, safety
chains should be attached to holes
on the trailer hitch platform. Always
leave just enough slack so the
combination can turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lb) needs to have
its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted, and
maintained properly.
Do not tap into the vehicle's
hydraulic brake system.
Auxiliary Battery
The auxiliary battery provision can
be used to supply electrical power
to additional equipment that may be
added, such as a slide-in camper.
If equipped, this relay will be on the
driver side of the vehicle, next to the
underhood electrical center.
Be sure to follow the proper
installation instructions included with
any electrical equipment that is
installed.
{Caution
Leaving electrical equipment on
for extended periods will drain the
battery. Always turn off electrical
equipment when not in use and
do not use equipment that
exceeds the maximum amperage
rating of 30 amps for the auxiliary
battery provision.
Trailer Wiring Harness
The vehicle is equipped with one of
the following wiring harnesses for
towing a trailer or hauling a slide-in
camper.
Black plate (75,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
Vehicle Care 10-75
{Caution
The wrong wheel can also cause
problems with bearing life, brake
cooling, speedometer or
odometer calibration, headlamp
aim, bumper height, vehicle
ground clearance, and tire or tire
chain clearance to the body and
chassis.
Whenever a wheel, wheel bolt,
or wheel nut is replaced on a dual
wheel setup, check the wheel nut
torque after 160, 1 600 and
10 000 km (100, 1,000 and 6,000 mi)
of driving. For proper torque, see
“Wheel Nut Torque” under
Capacities and Specifications on
page 12-2.
See If a Tire Goes Flat on
page 10-76 for more information. Used Replacement Wheels{Warning
Replacing a wheel with a used
one is dangerous. How it has
been used or how far it has been
driven may be unknown. It could
fail suddenly and cause a crash.
When replacing wheels, use a
new GM original equipment
wheel.
Tire Chains
{Warning
If the vehicle has dual wheels or
P265/65R18, P275/55R20,
LT265/70R17, LT265/70R18,
LT265/60R20, P285/50R20,
P285/45R22 or 285/45R22 size
tires, do not use tire chains. They
can damage the vehicle because
there is not enough clearance.
(Continued)
Warning (Continued)
Tire chains used on a vehicle
without the proper amount of
clearance can cause damage to
the brakes, suspension, or other
vehicle parts. The area damaged
by the tire chains could cause you
to lose control of the vehicle and
you or others may be injured in a
crash.
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size combination
and road conditions. Follow that
manufacturer's instructions. To
help avoid damage to the vehicle,
drive slowly, readjust, or remove
the device if it is contacting the
vehicle, and do not spin the
vehicle's wheels.
If you do find traction devices that
will fit, install them on the rear
tires.
