
Black plate (23,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-23
See your dealer for more
information on curb weights,
cargo weights, Cargo Weight
Rating, and the correct center of
gravity zone.Starting and
Operating
New Vehicle Break-In
{Caution
The vehicle does not need an
elaborate break-in. But it will
perform better in the long run if
you follow these guidelines:
.Keep the vehicle speed at
88 km/h (55 mph) or less for
the first 805 km (500 mi).
.Do not drive at any one
constant speed, fast or slow,
for the first 805 km (500 mi).
Do not make full-throttle
starts. Avoid downshifting to
brake or slow the vehicle.
.Avoid making hard stops for
the first 322 km (200 mi) or
so. During this time the new
brake linings are not yet(Continued)
Caution (Continued)
broken in. Hard stops with
new linings can mean
premature wear and earlier
replacement. Follow this
breaking-in guideline every
time you get new brake
linings.
.Do not tow a trailer during
break-in. SeeTrailer Towing
on page 9-71 for the trailer
towing capabilities of the
vehicle and more information.
Following break-in, engine speed
and load can be gradually
increased.
Adjustable Throttle and
Brake Pedal
If equipped, the position of the
throttle and brake pedals can be
changed.

Black plate (31,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-31
can move the shift lever away from
P (Park) without first pulling it toward
you. If you can, it means that the
shift lever was not fully locked into
P (Park).
Torque Lock
If you are parking on a hill and you
do not shift the transmission into
P (Park) properly, the weight of the
vehicle may put too much force on
the parking pawl in the
transmission. You may find it difficult
to pull the shift lever out of P (Park).
This is called torque lock. To
prevent torque lock, set the parking
brake and then shift into P (Park)
properly before you leave the driver
seat. To find out how, seeShifting
Into Park on page 9-30.
When you are ready to drive, move
the shift lever out of P (Park) before
you release the parking brake.
If torque lock does occur, you may
need to have another vehicle push
yours a little uphill to take some of
the pressure from the parking pawl in the transmission. You will then be
able to pull the shift lever out of
P (Park).
Shifting out of Park
This vehicle is equipped with an
electronic shift lock release system.
The shift lock release is
designed to:
.Prevent ignition key removal
unless the shift lever is in
P (Park).
.Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN and the
regular brake pedal is applied.
The shift lock release is always
functional except in the case of an
uncharged or low voltage (less than
9 volt) battery.
If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See Jump Starting on
page 10-87. To shift out of P (Park):
1. Apply the brake pedal.
2. Move the shift lever to the
desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, press the shift lever all
the way into P (Park).
3. Move the shift lever to the desired position.
If you are still having a problem
shifting, then have the vehicle
serviced soon.
This vehicle may have the Safety
Belt Assurance System, which may
prevent the vehicle from shifting out
of P (Park). See Safety Belt
Messages on page 5-37.

Black plate (71,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-71
7. Stop and have someone pick upand store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11-3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
If the vehicle is bi-fuel, see the
bi-fuel supplement. Do not tow a trailer during break-in.
See
New Vehicle Break-In on
page 9-23 for more information.
{Warning
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too
heavy, the brakes may not work
well or even at all. The driver and
passengers could be seriously
injured. The vehicle may also be
damaged; the resulting repairs
would not be covered by the
vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
{Caution
Pulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
See Vehicle Load Limits on
page 9-15 for more information
about the vehicle's maximum load
capacity.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” later in this
section.

Black plate (72,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-72 Driving and Operating
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy.
Successful, safe trailering takes
correct equipment, and it has to be
used properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are
important for your safety and that of
your passengers. Read this section
carefully before pulling a trailer.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how the rig is used.
Speed, altitude, road grades,
outside temperature, and how much
the vehicle is used to pull a trailer
are all important. It can depend on
any special equipment on the
vehicle, and the amount of tongueweight the vehicle can carry. See
“Weight of the Trailer Tongue”
later
in this section for more information.
Trailer weight rating (TWR) for 1500
series trucks is calculated assuming
the tow vehicle has the driver, a
front seat passenger, and all
required trailering equipment.
Weight of additional optional
equipment, passengers, and cargo
in the tow vehicle must be
subtracted from the trailer weight
rating.
Trailer weight rating (TWR) for
2500 and 3500 series trucks is
calculated assuming the tow vehicle
has only the driver but all required
trailering equipment. Weight of
additional optional equipment,
passengers, and cargo in the tow
vehicle must be subtracted from the
trailer weight rating. Ask your dealer for trailering
information or advice.
For kingpin weight and trailer
tongue weight information, see
“Weight of the Trailer Tongue”
later
in this section.
Use the following chart to determine
how much the vehicle can weigh,
based upon the vehicle model and
options.
Weights listed apply for
conventional trailers and fifth-wheel
trailers unless otherwise noted.

Black plate (73,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-73
VehicleAxle Ratio Maximum Trailer Weight GCWR (a)
1500 Series 2WD Crew Cab Standard Box 5.3L V8 3.234 219 kg (9,300 lb) 6 804 kg (15,000 lb)
6.2L V8 3.234 128 kg (9,100 lb) 6 804 kg (15,000 lb)
1500 Series 2WD Crew Cab Short Box (b) 5.3L V8 3.424 264 kg (9,400 lb) 6 804 kg (15,000 lb)
6.2L V8 3.234 173 kg (9,200 lb) 6 804 kg (15,000 lb)
1500 Series 4WD Crew Cab Standard Box 5.3L V8 3.424 128 kg (9,100 lb) 6 804 kg (15,000 lb)
6.2L V8 3.233 992 kg (8,800 lb) 6 804 kg (15,000 lb)
1500 Series 4WD Crew Cab Short Box (b) 5.3L V8 3.424 173 kg (9,200 lb) 6 804 kg (15,000 lb)
6.2L V8 3.234 037 kg (8,900 lb) 6 804 kg (15,000 lb)
2500 Series 2WD Crew Cab Standard Box
6.0L V8 3.734 445 kg (9,800 lb) 7 257 kg (16,000 lb)
6.0L V8 –Conventional Trailer 4.105 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 –Fifth-Wheel Trailer 4.106 486 kg (14,300 lb) 9 299 kg (20,500 lb)

Black plate (74,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-74 Driving and Operating
VehicleAxle Ratio Maximum Trailer Weight GCWR (a)
2500 Series 4WD Crew Cab Standard Box 6.0L V8 3.734 309 kg (9,500 lb) 7 257 kg (16,000 lb)
6.0L V8 –Conventional Trailer 4.105 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 –Fifth-Wheel Trailer 4.106 350 kg (14,000 lb) 9 299 kg (20,500 lb)
3500 Series 2WD Crew Cab Standard Box
6.0L V8 3.734 355 kg (9,600 lb) 7 257 kg (16,000 lb)
6.0L V8 –Conventional Trailer 4.105 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 Fifth-Wheel Trailer 4.106 396 kg (14,100 lb) 9 299 kg (20,500 lb)
3500 Series 2WD Crew Cab Long Box
6.0L V8 (Single Rear Wheels) 3.734 309 kg (9,500 lb) 7 257 kg (16,000 lb)
6.0L V8 (Single Rear Wheels)
Conventional Trailer 4.10
5 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 (Single Rear Wheels)
Fifth-Wheel Trailer 4.10
6 350 kg (14,000 lb) 9 299 kg (20,500 lb)
6.0L V8 (Dual Rear Wheels) 3.734 173 kg (9,200 lb) 7 257 kg (16,000 lb)
6.0L V8 (Dual Rear Wheels) 4.106 214 kg (13,700 lb) 9 299 kg (20,500 lb)
3500 Series 4WD Crew Cab Standard Box 6.0L V8 3.734 264 kg (9,400 lb) 7 257 kg (16,000 lb)

Black plate (75,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-75
VehicleAxle Ratio Maximum Trailer Weight GCWR (a)
6.0L V8 –Conventional Trailer 4.105 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 –Fifth-Wheel Trailer 4.106 305 kg (13,900 lb) 9 299 kg (20,500 lb)
3500 Series 4WD Crew Cab Long Box 6.0L V8 (Single Rear Wheels) 3.734 173 kg (9,200 lb) 7 257 kg (16,000 lb)
6.0L V8 (Single Rear Wheels)
Conventional Trailer 4.10
5 897 kg (13,000 lb) 9 299 kg (20,500 lb)
6.0L V8 (Single Rear Wheels)
Fifth-Wheel Trailer 4.10
6 214 kg (13,700 lb) 9 299 kg (20,500 lb)
6.0L V8 (Dual Rear Wheels) 3.733 992 kg (8,800 lb) 7 257 kg (16,000 lb)
6.0L V8 (Dual Rear Wheels) 4.106 033 kg (13,300 lb) 9 299 kg (20,500 lb)
(a) The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle
and trailer including any passengers, cargo, equipment, and conversions. The GCWR for the vehicle should not be
exceeded.
(b) This model is neither designed nor intended to tow fifth-wheel or gooseneck trailers.
Ask your dealer for trailering information or advice.

Black plate (76,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-76 Driving and Operating
Weight of the Trailer Tongue
The tongue load (1) of any trailer is
very important because it is also
part of the vehicle weight. The
Gross Vehicle Weight (GVW)
includes the curb weight of the
vehicle, any cargo carried in it, and
the people who will be riding in the
vehicle as well as trailer tongue
weight. Vehicle options, equipment,
passengers and cargo in the vehicle
reduce the amount of tongue weight
the vehicle can carry, which will also
reduce the trailer weight the vehicle
can tow.
Trailer tongue weight (1) should be
10–15% and fifth-wheel or
gooseneck kingpin weight should be
15–25% of the loaded trailer
weight (2) up to the maximums for
vehicle series and hitch type.