
Black plate (35,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
Vehicle Care 10-35
fill plug hole, located on the rear
axle. Add only enough fluid to
reach the proper level.
.For all 6.0L 2500HD Series
applications, the proper level is
from 0 mm to 13 mm (0 to 0.5 in)
below the bottom of the fill plug
hole, located on the rear axle.
Add only enough fluid to reach
the proper level.
.For all 6.6L Duramax Diesel
2500HD Series applications and
all 3500 Series applications, the
proper level is from 17 mm to
21 mm (0.6 in to 0.8 in) below
the bottom of the fill plug hole,
located on the rear axle. Add
only enough fluid to reach the
proper level.
What to Use
Refer toRecommended Fluids and
Lubricants on page 11-12 to
determine what kind of lubricant
to use.
Noise Control System
The following information relates to
compliance with federal noise
emission standards for vehicles with
a Gross Vehicle Weight Rating
(GVWR) of more than 4 536 kg
(10,000 lb). The noise control
system warranty is given in your
warranty manual.
These standards apply only to
vehicles sold in the United States.
Federal law prohibits the following
acts or the causing thereof:
1. The removal or rendering inoperative by any person, other
than for purposes of
maintenance, repair or
replacement, of any device or
element of design incorporated
into any new vehicle for the
purpose of noise control, prior to
its sale or delivery to the ultimate
purchaser or while it is in use; or 2. The use of the vehicle after such
device or element of design has
been removed or rendered
inoperative by any person.
Among those acts presumed to
constitute tampering are the acts
listed below.
Insulation:
Removal of the noise shields or any
underhood insulation.
Engine:
Removal or rendering engine speed
governor, if the vehicle has one,
inoperative so as to allow engine
speed to exceed manufacturer
specifications.
Fan and Drive:
.Removal of fan clutch, if the
vehicle has one, or rendering
clutch inoperative.
.Removal of the fan shroud, if the
vehicle has one.

Black plate (58,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
10-58 Vehicle Care
(single/dual). The speed rating is
the maximum speed a tire is
certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount of
air inside the tire pressing
outward on each square inch of
the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight
:The
combined weight of optional
accessories. Some examples of
optional accessories are
automatic transmission, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width. Belt
:A rubber coated layer of
cords between the plies and the
tread. Cords may be made from
steel or other reinforcing
materials.
Bead
:The tire bead contains
steel wires wrapped by steel
cords that hold the tire onto
the rim.
Bias Ply Tire
:A pneumatic tire
in which the plies are laid at
alternate angles less than
90 degrees to the centerline of
the tread.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in kPa (kilopascal)
or psi (pounds per square inch)
before a tire has built up heat
from driving. See Tire Pressure
on page 10-61.
Curb Weight
:The weight of a
motor vehicle with standard and
optional equipment including the maximum capacity of fuel, oil,
and coolant, but without
passengers and cargo.
DOT Markings
:A code molded
into the sidewall of a tire
signifying that the tire is in
compliance with the U.S.
Department of Transportation
(DOT) Motor Vehicle Safety
Standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight
Rating. See Vehicle Load Limits
on page 9-15.
GAWR FRT
:Gross Axle Weight
Rating for the front axle. See
Vehicle Load Limits on
page 9-15.

Black plate (59,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
Vehicle Care 10-59
GAWR RR:Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits on
page 9-15.
Intended Outboard Sidewall
:
The side of an asymmetrical tire
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric
unit for air pressure.
Light Truck (LT-Metric) Tire
:A
tire used on light duty trucks and
some multipurpose passenger
vehicles.
Load Index
:An assigned
number ranging from 1 to 279
that corresponds to the load
carrying capacity of a tire.
Maximum Inflation Pressure
:
The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is
molded onto the sidewall. Maximum Load Rating
:The
load rating for a tire at the
maximum permissible inflation
pressure for that tire.
Maximum Loaded Vehicle
Weight
:The sum of curb
weight, accessory weight,
vehicle capacity weight, and
production options weight.
Normal Occupant Weight
:The
number of occupants a vehicle
is designed to seat multiplied by
68 kg (150 lb). See Vehicle Load
Limits on page 9-15.
Occupant Distribution
:
Designated seating positions.
Outward Facing Sidewall
:The
side of an asymmetrical tire that
has a particular side that faces
outward when mounted on a
vehicle. The side of the tire that
contains a whitewall, bears
white lettering, or bears
manufacturer, brand, and/or model name molding that is
higher or deeper than the same
moldings on the other sidewall
of the tire.
Passenger (P-Metric) Tire
:A
tire used on passenger cars and
some light duty trucks and
multipurpose vehicles.
Recommended Inflation
Pressure
:Vehicle
manufacturer's recommended
tire inflation pressure as shown
on the tire placard. See Tire
Pressure on page 10-61 and
Vehicle Load Limits on
page 9-15.
Radial Ply Tire
:A pneumatic
tire in which the ply cords that
extend to the beads are laid at
90 degrees to the centerline of
the tread.
Rim
:A metal support for a tire
and upon which the tire beads
are seated.

Black plate (60,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
10-60 Vehicle Care
Sidewall:The portion of a tire
between the tread and the bead.
Speed Rating
:An
alphanumeric code assigned to
a tire indicating the maximum
speed at which a tire can
operate.
Traction
:The friction between
the tire and the road surface.
The amount of grip provided.
Tread
:The portion of a tire that
comes into contact with
the road.
Treadwear Indicators
:Narrow
bands, sometimes called wear
bars, that show across the tread
of a tire when only 1.6 mm
(1/16 in) of tread remains. See
When It Is Time for New Tires
on page 10-69. UTQGS (Uniform Tire Quality
Grading Standards)
:A tire
information system that provides
consumers with ratings for a
tire's traction, temperature, and
treadwear. Ratings are
determined by tire
manufacturers using
government testing procedures.
The ratings are molded into the
sidewall of the tire. See Uniform
Tire Quality Grading on
page 10-72.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated
cargo load. See Vehicle Load
Limits on page 9-15. Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a
vehicle showing the vehicle
capacity weight and the original
equipment tire size and
recommended inflation pressure.
See “Tire and Loading
Information Label” underVehicle
Load Limits on page 9-15.

Black plate (61,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
Vehicle Care 10-61
Tire Pressure
Tires need the correct amount of
air pressure to operate
effectively.
{Caution
Neither tire underinflation nor
overinflation is good.
Underinflated tires, or tires
that do not have enough air,
can result in:
.Tire overloading and
overheating which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy.
(Continued)
Caution (Continued)
Overinflated tires, or tires that
have too much air, can
result in:
.Unusual wear.
.Poor handling.
.Rough ride.
.Needless damage from
road hazards.
The Tire and Loading
Information label on the vehicle
indicates the original equipment
tires and the correct cold tire
inflation pressures. The
recommended pressure is the
minimum air pressure needed to
support the vehicle's maximum
load carrying capacity.
For additional information
regarding how much weight the
vehicle can carry, and an example of the Tire and Loading
Information label, see
Vehicle
Load Limits on page 9-15. How
the vehicle is loaded affects
vehicle handling and ride
comfort. Never load the vehicle
with more weight than it was
designed to carry.
When to Check
Check the tires once a month
or more.
Do not forget the spare tire,
if the vehicle has one. See
Full-Size Spare Tire on
page 10-88 for additional
information.
How to Check
Use a good quality pocket-type
gauge to check tire pressure.
Proper tire inflation cannot be
determined by looking at the tire.
Check the tire inflation pressure
when the tires are cold, meaning

Black plate (70,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
10-70 Vehicle Care
maintenance affect how fast aging
takes place. GM recommends that
tires, including the spare if
equipped, be replaced after six
years, regardless of tread wear. The
tire manufacturer date is the last
four digits of the DOT Tire
Identification Number (TIN) which is
molded into one side of the tire
sidewall. The first two digits
represent the week (01-52) and the
last two digits, the year. For
example, the third week of the year
2010 would have a four-digit DOT
date of 0310.
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be free
of grease, gasoline or other
substances that can deteriorate
rubber.Parking for an extended period can
cause flat spots on the tires that
may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires or
raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria
Specification (TPC Spec)
system rating. When
replacement tires are needed,
GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec
system considers over a dozen
critical specifications that impact
the overall performance of the
vehicle, including brake system
performance, ride and handling,
traction control, and tire
pressure monitoring
performance. GM's TPC Spec
number is molded onto the tire's
sidewall near the tire size. If the
tires have an all-season tread
design, the TPC Spec number
will be followed by MS for mud
and snow. See
Tire Sidewall
Labeling on page 10-54 for
additional information.
GM recommends replacing worn
tires in complete sets of four (six
for dual rear wheels). Uniform
tread depth on all tires will help
to maintain the performance of
the vehicle. Braking and
handling performance may be
adversely affected if all the tires
are not replaced at the same
time. If proper rotation and
maintenance have been done,
all four tires (six for dual rear
wheels) should wear out at