towing GMC SIERRA 2018 Owner's Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
310 Driving and Operating
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Conventional
Trailer 3.42 5 035 kg (11,100 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Gooseneck/
Fifth-Wheel Trailer 3.42 4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 –Conventional Trailer 3.735 035 kg (11,100 lb) 7 575 kg (16,700 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.73
4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 264 kg (9,400 lb) 6 804 kg (15,000 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.23
4 082 kg (9,000 lb) 6 804 kg (15,000 lb)
6.2L V8 –Conventional Trailer 3.425 670 kg (12,500 lb) 8 255 kg (18,200 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42
5 262 kg (11,600 lb) 8 255 kg (18,200 lb)
1500 Series 2WD Crew Cab Standard Box 5.3L V8 3.082 858 kg (6,300 lb) 5 443 kg (12,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 311
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 –Conventional Trailer 3.424 218 kg (9,300 lb) 6 804 kg (15,000 lb)
5.3L V8, 6-speed automatic
transmission –Gooseneck/
Fifth-Wheel Trailer 3.42
3 856 kg (8,500 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission –Gooseneck/
Fifth-Wheel Trailer 3.42
3 674 kg (8,100 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Conventional
Trailer 3.42
4 944 kg (10,900 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Gooseneck/
Fifth-Wheel Trailer 3.42
4 808 kg (10,600 lb) 7 575 kg (16,700 lb)
5.3L V8 –Conventional Trailer 3.734 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.73
4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 218 kg (9,300 lb) 6 804 kg (15,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
312 Driving and Operating
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.23 3 765 kg (8,300 lb) 6 804 kg (15,000 lb)
6.2L V8 –Conventional Trailer 3.425 398 kg (11,900 lb) 8 029 kg (17,700 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42
4 763 kg (10,500 lb) 8 029 kg (17,700 lb)
1500 Series 2WD Crew Cab Short Box (b) 4.3L V6 3.232 495 kg (5,500 lb) 4 990 kg (11,000 lb)
5.3L V8 3.082 903 kg (6,400 lb) 5 443 kg (12,000 lb)
5.3L V8, 6-speed automatic
transmission 3.42
4 264 kg (9,400 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission 3.42
4 218 kg (9,300 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package 3.42
4 990 kg (11,000 lb) 7 575 kg (16,700 lb)
5.3L V8 3.734 990 kg (11,000 lb) 7 575 kg (16,700 lb)
6.2L V8 3.234 218 kg (9,300 lb) 6 804 kg (15,000 lb)
6.2L V8 3.425 670 kg (12,500 lb) 8 255 kg (18,200 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
314 Driving and Operating
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 3.08 2 812 kg (6,200 lb) 5 443 kg (12,000 lb)
5.3L V8 –Gooseneck/Fifth Wheel 3.08 2 767 kg (6,100 lb) 5 443 kg (12,000 lb)
5.3L V8 –Conventional Trailer 3.424 173 kg (9,200 lb) 6 804 kg (15,000 lb)
5.3L V8 –Gooseneck/Fifth Wheel 3.42 4 082 kg (9,000 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package 3.42
4 899 kg (10,800 lb) 7 575 kg (16,700 lb)
5.3L V8 3.734 899 kg (10,800 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 128 kg (9,100 lb) 6 804 kg (15,000 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.23
3 901 kg (8,600 lb) 6 804 kg (15,000 lb)
6.2L V8 –Conventional Trailer 3.425 352 kg (11,800 lb) 8 029 kg (17,700 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42
4 990 kg (11,000 lb) 8 029 kg (17,700 lb)
1500 Series 4WD Crew Cab Standard Box 5.3L V8 –Conventional Trailer 3.082 767 kg (6,100 lb) 5 443 kg (12,000 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.08
2 722 kg (6,000 lb) 5 443 kg (12,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 315
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
5.3L V8 –Conventional Trailer 3.424 128 kg (9,100 lb) 6 804 kg (15,000 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42
3 674 kg (8,100 lb) 6 804 kg (15,000 lb)
5.3L V8 –8-speed automatic
transmission with Enhanced
Towing Package - Conventional
Trailer 3.42
4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package –Gooseneck/
Fifth Wheel Trailer 3.42
4 627 kg (10,200 lb) 7 575 kg (16,700 lb)
5.3L V8 –Conventional Trailer 3.734 853 kg (10,700 lb) 7 575 kg (16,700 lb)
5.3L V8 –Gooseneck/Fifth-Wheel
Trailer 3.73
4 627 kg (10,200 lb) 7 575 kg (16,700 lb)
6.2L V8 –Conventional Trailer 3.234 082 kg (9,000 lb) 6 804 kg (15,000 lb)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.23
3 629 kg (8,000 lb) 6 804 kg (15,000 lb)
6.2L V8 –Conventional Trailer 3.425 307 kg (11,700 lb) 8 029 kg (17,700 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
316 Driving and Operating
1500/2500/3500 Series Pickups–SAE J2807 Compliant
Vehicle Axle Ratio Maximum Trailer
Weight (c) GCWR (a)
6.2L V8 –Gooseneck/Fifth-Wheel
Trailer 3.42 4 627 kg (10,200 lb) 8 029 kg (17,700 lb)
1500 Series 4WD Crew Cab Short Box (b) 4.3L V6 3.42 3 175 kg (7,000 lb) 5 806 kg (12,800 lb)
5.3L V8 3.08 2 767 kg (6,100 lb) 5 443 kg (12,000 lb)
5.3L V8 3.42 4 128 kg (9,100 lb) 6 804 kg (15,000 lb)
5.3L V8, 8-speed automatic
transmission with Enhanced
Towing Package 3.42 4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
5.3L V8 3.73 4 853 kg (10,700 lb) 7 575 kg (16,700 lb)
6.2L V8 3.23 4 128 kg (9,100 lb) 6 804 kg (15,000 lb)
6.2L V8 3.42 5 307 kg (11,700 lb) 8 029 kg (17,700 lb)
1500 Series 4WD Regular Cab Long Box 4.3L V6 –Conventional Trailer 3.423 357 kg (7,400 lb) 5 806 kg (12,800 lb)
4.3L V6 –Gooseneck/Fifth Wheel 3.42 3 311 kg (7,300 lb) 5 806 kg (12,800 lb)
5.3L V8 –Conventional Trailer 3.082 948 kg (6,500 lb) 5 443 kg (12,000 lb)
5.3L V8 –Gooseneck/Fifth Wheel 3.08 2 903 kg (6,400 lb) 5 443 kg (12,000 lb)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 325
Total Weight on the Vehicle's
Tires
Be sure the vehicle's tires are
inflated to the inflation pressures
found on the Certification/Tire label
on the center pillar or seeVehicle
Load Limits 0248. Make sure not to
exceed the GVWR limit for the
vehicle, or the RGAWR, with the tow
vehicle and trailer fully loaded for
the trip including the weight of the
trailer tongue. If using a
weight-distributing hitch, make sure
not to exceed the RGAWR before
applying the weight distribution
spring bars.
Weight of the Trailering
Combination
It is important that the combination
of the tow vehicle and trailer does
not exceed any of its weight
ratings —GCWR, GVWR, RGAWR,
Trailer Weight Rating, or Tongue
Weight. The only way to be sure it 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.
Towing Equipment
Hitches
The correct hitch equipment helps
maintain combination control. Many
trailers can be towed with a
weight-carrying hitch which simply
features 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 among the
tow vehicle and trailer axles.
Fifth-wheel and gooseneck hitches
may also be used. See
“Weight of
the Trailer Tongue” underTrailer
Towing 0307 for rating limits with
various hitch types. If a step-bumper hitch will be used,
the bumper could be damaged in
sharp turns. Make sure there
is ample room when turning to avoid
contact between the trailer and the
bumper.
Consider using sway controls with
any trailer. Ask a trailering
professional about sway controls or
refer to the trailer manufacturer's
recommendations and instructions.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 327
Fifth-wheel or gooseneck kingpin
weight should be 15 to 25% of the
trailer weight up to the maximum
amount specified in the trailering
chart for the vehicle. See“Weight of
the Trailer” underTrailer Towing
0 307.
The hitch should be located in the
pickup bed so that its centerline is
over or slightly in front of the rear
axle. Take care that it is not so far
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.
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 is being
towed with a factory-installed step
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) must be
equipped with its own brake system,
with brakes working on all axles.
Trailer braking equipment
conforming to Canadian Standards
Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State and local regulations may also
require the trailer to have its own
braking system if loaded above a
certain threshold. These
requirements vary from state to
state.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
328 Driving and Operating
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.
Basic Trailer Wiring
All regular, double cab, and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy-duty trailering, the harness is
secured to the vehicle's frame
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.Use only a round, seven-wire
connector with flat blade terminals
meeting SAE J2863 specifications
for proper electrical connectivity.
The seven-wire harness contains
the following trailer circuits:
.
Green/Violet: Right Stop/Turn
Signal
. Yellow/Gray: Left Stop/Turn
Signal
. Gray/Brown: Taillamps/Parking
Lamps
. White/Green: Back-up Lamps
. Red/Green: Battery Feed
. White: Ground
. Blue: Electric Trailer Brake
The fuse for the electric trailer brake
circuit is installed in the underhood
electrical center, but the wires may
not be connected. They should be
connected by your dealer or a
qualified service center. To control
electric trailer brakes, a trailer brake
controller needs to be installed on
the vehicle by your dealer or a qualified service center, see
“Electric Brake Control Wiring
Provisions”
later in this section.
Heavy-Duty Trailer Wiring Harness
Package
For vehicles equipped with
heavy-duty trailering, the harness
connector is mounted in the bumper.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
330 Driving and Operating
.Black: Ground
Be sure to consult the aftermarket
electric brake controller owner ’s
manual to determine wire color
coding of the electric trailer brake
controller. The wire colors on the
brake controller may be different
from the vehicle.
The electric trailer brake controller
should be installed by your dealer or
a qualified service center.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on.
Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See Tow/Haul
Mode 0271.
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0307. Tow/Haul is
most useful under the following
driving conditions:
. When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
. When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic. .
When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
selection of Tow/Haul when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and
transmission driving characteristics
and reduced fuel economy. Tow/
Haul is recommended only when
pulling a heavy trailer or a large or
heavy load.
Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brakes.