2019 GMC SIERRA rear axle

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
240 Driving and Operating
{Warning
If equipped with four-wheel drive,
the vehicle will be free to roll if the
transfer case is in N (Neutral),
even when the shift lever is in
P (Park). You or someone else
could be seriously injured. Be
sure the transfer case is in a drive
gear—2
m, 4m, or 4n—or set the
parking brake before placing the
transfer case in N (Neutral). See
Shifting Into Park 0229.
Caution
Extended high-speed operation in
4
nmay damage or shorten the
life of the drivetrain.
An engagement noise and bump is
normal when shifting between 4
n
and 4mor N (Neutral), with the
engine running. Shifting into 4
nwill turn Traction
Control and StabiliTrak/Electronic
Stability Control (ESC) off. See
Traction Control/Electronic Stability
Control 0247.
Automatic Transfer Case
Two-Speed Transfer Case
If equipped, the transfer case
controls are used to shift into and
out of four-wheel drive.
To shift the transfer case, press the
desired button. The graphic in the
instrument cluster will flash while a shift is in progress. The graphic
displayed will change to indicate the
setting requested.
When the shift is complete the
graphic will stop flashing. The DIC
message turns off once the shift is
complete. If the transfer case
cannot complete a shift request, it
will go back to its last chosen
setting.
The settings are:
N (Neutral) :
Use only when the
vehicle needs to be towed. See
Recreational Vehicle Towing 0404
or
Towing the Vehicle 0403.
2
m(Two-Wheel Drive High) : Use
for driving on most streets and
highways. The front axle is not
engaged. This setting provides the
best fuel economy.
AUTO (Automatic Four-Wheel
Drive) : Use when road surface
conditions are variable. When
driving in AUTO, the front axle is
engaged, and the vehicle's power is
sent to the front and rear wheels

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
244 Driving and Operating
cannot complete a shift request, it
will go back to its last chosen
setting.
The settings are:
2
m(Two-Wheel Drive High) :Use
for driving on most streets and
highways. The front axle is not
engaged. This setting provides the
best fuel economy.
4
m(Four-Wheel Drive High) : Use
this setting when extra traction is
needed, such as when driving on
snowy or icy roads, when
off-roading, or when plowing snow.
AUTO (Automatic Four-Wheel
Drive)
Use when road surface conditions
are variable. When driving in AUTO,
the front axle is engaged, and the
vehicle's power is sent to the front
and rear wheels automatically
based on driving conditions. This
setting provides slightly lower fuel
economy than 2
m. Shifts between 2
m, 4m, and AUTO
Any of these shifts can be made at
normal driving speed.
The actual 4x4 shift request is only
made after the button is released.
The 4x4 graphic will remain flashing
until the shift request has
completed. A DIC message
displays.
Once the 4x4 shift has completed,
the DIC message disappears, the
4x4 graphic stops flashing, and the
current setting is indicated.
The actual 4x4 shift request is only
made after the button is released.
The 4x4 graphic will remain flashing
until the shift request has
completed.
A DIC message displays. Once the
4x4 shift has completed, the DIC
message disappears, the 4x4
graphic stops flashing, and the
current setting is indicated.Brakes
Antilock Brake
System (ABS)
This vehicle has an Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
0 155.
If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses the wheels are
slowing down. If one of the wheels
is about to stop rolling, the computer
will separately work the brakes at
each wheel.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Driving and Operating 255
When Terrain Mode is selected:
.Auto Engine Start/Stop will be
disabled.
. The Terrain Mode indicator
displays on the instrument
cluster.
Limited-Slip Differential
If equipped, the limited-slip
differential can give more traction on
snow, mud, ice, sand, or gravel.
It works like a standard axle most of
the time, but when traction is low,
this feature allows the drive wheel
with the most traction to move the
vehicle. For vehicles with the
limited-slip differential, driven under
severe conditions, the rear axle fluid
should be changed. See
Maintenance Schedule 0420.
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.
Cruise Control
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.
If equipped with cruise control, a
speed of about 40 km/h (25 mph) or
more can be maintained without
keeping your foot on the
accelerator. Cruise control does not
work at speeds below about
40 km/h (25 mph).
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak/Electronic
Stability Control (ESC) begins to
limit wheel spin, the cruise control

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Driving and Operating 287
must be below all of the maximum
weight ratings for the vehicle,
including:
.GCWR: Gross Combined Weight
Rating
. GVWR: Gross Vehicle Weight
Rating
. Maximum Trailer Weight Rating
. GAWR-RR: Gross Axle Weight
Rating-Rear
. Maximum Trailer Tongue Weight
Rating
See “Weight-Distributing Hitch
Adjustment” underTowing
Equipment 0290 to determine if
equalizer bars are required to obtain
the maximum trailer weight rating.
See “Trailer Brakes” underTowing
Equipment 0290 to determine if
brakes are required based on your
trailer's weight.
The only way to be sure the weight
is not exceeding any of these
ratings is to weigh the tow vehicle
and trailer combination, fully loaded
for the trip, getting individual
weights for each of these items. A trailering information label on the
driver's side door B-pillar shows tow
rating information for the vehicle.
{Warning
You and others could be seriously
injured or killed if the trailer is too
heavy or the trailer brakes are
inadequate for the load. The
vehicle may be damaged, and the
repairs would not be covered by
the vehicle warranty.
Only tow a trailer if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer.
Gross Combined Weight
Rating (GCWR)
GCWR is the total allowable weight
of the completely loaded vehicle
and trailer including any fuel,
passengers, cargo, equipment, and
accessories. Do not exceed the
GCWR for your vehicle. The GCWR
for the vehicle is on the Trailering
Information Label.
To check that the weight of the
vehicle and trailer are within the
GCWR for the vehicle, follow these
steps:
1. Start with the "curb weight" from the Trailering Information
Label.
2. Add the weight of the trailer loaded with cargo and ready
for the trip.
3. Add the weight of all passengers.
4. Add the weight of all cargo in the vehicle.
5. Add the weight of hitch hardware such as a draw bar,
ball, load equalizer bars,
or sway bars.
6. Add the weight of any accessories or aftermarket
equipment added to the
vehicle.
The resulting weight cannot exceed
the GCWR value shown on the
Trailering Information Label.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
290 Driving and Operating
weights and distribution are
appropriate for your vehicle. If the
trailer weight is too high, it may be
possible to transfer some of the
cargo into your vehicle. If the trailer
tongue weight is too high or too low,
it may be possible to rearrange
some of the cargo inside of the
trailer.
Do not exceed the maximum
allowable tongue weight for the
vehicle. Use the shortest hitch
extension that will position the hitch
ball closest to the vehicle. This will
help reduce the effect of trailer
tongue weight on the trailer hitch
and rear axle.
If a cargo carrier is used in the
trailer hitch receiver, choose a
carrier that positions the load as
close to the vehicle as possible.
Make sure the total weight,
including the carrier, is no more than
half of the maximum allowable
tongue weight for the vehicle or
227 kg (500 lb), whichever is less.Rear Gross Axle Weight Rating
(GAWR-RR)
The GAWR-RR is the total weight
that can be supported by the rear
axle of the vehicle. Do not exceed
the GAWR-RR for the vehicle, with
the tow vehicle and trailer fully
loaded for the trip including the
weight of the trailer tongue. If using
a weight-distributing hitch, do not
exceed the GAWR-RR before
applying the weight distribution
spring bars.
The GAWR-RR for the vehicle is on
the Trailering Information Label.Ask your dealer for trailering
information or assistance.
Towing Equipment
Hitches
Always use the correct hitch
equipment for your vehicle.
Crosswinds, large trucks going by,
and rough roads can affect the
trailer and the hitch.
Proper hitch equipment for your
vehicle helps maintain control of the
vehicle-trailer combination. Many
trailers can be towed using a
weight-carrying hitch which has a
coupler latched to the hitch ball, or a
tow eye latched to a pintle hook.
Other trailers may require a
weight-distributing hitch that uses
spring bars to distribute the trailer
tongue weight between your vehicle
and trailer axles. See
“Maximum
Trailer Tongue Weight” underTrailer
Towing 0286 for weight limits with
various hitch types.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Driving and Operating 293
chains may be attached to the
attaching points on the bumper;
otherwise, safety chains should be
attached to holes on the trailer hitch.
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. Always leave enough slack in
the safety chains to allow the
combination to turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
Loaded trailers over 900 kg
(2,000 lb) must be equipped with
brake systems and with brakes for
each axle. Trailer braking equipment
conforming to Canadian Standards
Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State or local regulations may
require trailers to have their own
braking system if the loaded weight
of the trailer exceeds certain
minimums that can vary from state
to state. Read and follow the
instructions for the trailer brakes sothey are installed, adjusted, and
maintained properly. Never attempt
to tap into your vehicle's hydraulic
brake system. If you do, both the
vehicle antilock brakes and the
trailer brakes may not function,
which could result in a crash.
Trailer Wiring Harness
If the vehicle is not equipped with a
trailer connector on the rear bumper,
a 7-wire trailering harness is tied to
the vehicles frame. The harness
requires the installation of a trailer
connector, which is available
through your dealer.
If equipped, the trailer wiring
harness, with a 7-pin connector and
a 4-pin connector, is mounted on
the vehicle's rear bumper.
1. Ground
2. Taillamps
3. Left Turn/Brake
4. Right Turn/Brake

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
312 Driving and Operating
Adding a Snow Plow or
Similar Equipment
Caution
Do not exceed 72 km/h (45 mph)
with a snow plow mounted to the
vehicle. The vehicle could
overheat and be damaged.
Before installing a snow plow on the
vehicle, follow these guidelines:
Caution
If the vehicle does not have the
snow plow prep package, RPO
VYU, adding a plow can damage
the vehicle, and the repairs would
not be covered by the vehicle
warranty. Unless the vehicle was
built to carry a snow plow, do not
add one to the vehicle. If the
vehicle has RPO VYU, then the
payload the vehicle can carry will
be reduced when a snow plow is (Continued)
Caution (Continued)
installed. The vehicle can be
damaged if either the front or rear
axle ratings or the Gross Vehicle
Weight Rating (GVWR) are
exceeded.
The plow the vehicle can carry
depends on many things, such as:
. The options the vehicle came
with, and the weight of those
options.
. The weight and number of
passengers to be carried.
. The weight of items added to the
vehicle, like a tool box or
truck cap.
. The total weight of any
additional cargo to be carried.
For example, if the snow plow
weighs 318 kg (700 lb), the total
weight of all occupants and cargo
inside the cab should not exceed
135 kg (300 lb). This means that you
may only be able to carry one
passenger. Even this may be too much if there is other equipment
already adding to the weight of the
vehicle.
To safely carry a snow plow on the
vehicle:
.
Follow all aftermarket snow plow
manufacturer ’s instructions for
the operation and transportation
of the snow plow.
. With a snow plow attached, the
engine coolant temperature
gauge may show a higher
temperature than while driving
without one. The snow plow
could block the airflow to the
radiator. This could be more
noticeable as vehicle speed
increases. At speeds above
72 km (45 mph), this may cause
the engine coolant to overheat.
. To increase the airflow, move the
snow plow blade postion.
. If driving more than 24 km
(15 mi), angle the plow blade
position.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Driving and Operating 313
.Make sure the weight on the
front and rear axles does not
exceed the axle rating for each.
. For the front axle, if more cargo
or passengers must be carried,
appropriate counter ballast must
be installed rear of the rear axle.
Counter ballast must be properly
secured so it will not move
during driving.
. Rear ballast may be required to
ensure a proper front and rear
weight distribution ratio, even
though the actual weight at the
front axle may be less than the
front axle rating.
. The snow plow manufacturer or
installer can assist in
determining the amount of rear
ballast required, to help make
sure the snow plow/vehicle
combination does not exceed
the GVW rating, the front and
rear axle ratings, and the front
and rear weight distribution ratio.
. The total vehicle must not
exceed the GVW rating. Front axle reserve capacity is the
difference between the Gross Axle
Weight Rating (GAWR) and the front
axle weight of the vehicle with full
fuel and passengers. This is the
amount of weight that can be added
to the front axle before reaching the
front GAWR.
United States
Canada
The front axle reserve capacity for
the vehicle is in the lower right
corner of the Certification/Tire label.