2012 GMC Sierra Owners Manual

is stuck in sand, mud, ice or snow, and you want to “rock” the vehicle to attempt to free it. It may also be necessary to turn off the system when driving in extreme off-road conditions where high wheel spin is required. See If the Vehicle Is Stuck on page 9‑15. When the transfer case is in 4LO, the stability system is automatically disabled, the StabiliTrak light comes on, and the appropriate message will appear on the DIC. Both traction control and StabiliTrak are automatically disabled in this condition. Traction Control Operation The TCS is part of the StabiliTrak system. Traction control limits wheel spin by reducing engine power to the wheels (engine speed management) and by applying

brakes to each individual wheel (brake-traction control) as necessary. The TCS is enabled automatically when the vehicle is started. It will activate and the StabiliTrak light will flash if it senses that any of the wheels are spinning or beginning to lose traction while driving. If traction control is turned off, only the brake-traction control portion of traction control will work. The engine speed management will be disabled. In this mode, engine power is not reduced automatically and the driven wheels can spin more freely. This can cause the brake-traction control to activate constantly. Notice: If the wheel(s) of one axle is allowed to spin excessively while the StabiliTrak®, ABS, brake warning lights, and any relevant DIC messages are displayed, the transfer case could be damaged. The repairs would not be covered by the vehicle warranty. Reduce engine power and do not spin the

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wheel(s) excessively while these lights and messages are displayed. The TCS may activate on dry or rough roads or under conditions such as heavy acceleration while turning or abrupt upshifts/downshifts of the transmission. When this happens, a reduction in acceleration may be noticed, or a noise or vibration may be heard. This is normal. If cruise control is being used when the system activates, the StabiliTrak light will flash and cruise control will automatically disengage. Cruise control may be reengaged when road conditions allow. See Cruise Control on page 9‑58. StabiliTrak may also turn off automatically if it determines that a problem exists with the system. If the problem does not clear itself after restarting the vehicle, see your dealer for service.

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Driving and Operating

Non-hybrid vehicles with StabiliTrak have a Trailer Sway Control (TSC) feature. See Trailer Sway Control (TSC) on page 9‑105. Non-hybrid vehicles with StabiliTrak have a Hill Start Assist (HSA) feature. See Hill Start Assist (HSA) on page 9‑54. Adding non‐dealer accessories can affect the vehicle's performance. See Accessories and Modifications on page 10‑3.

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. So, do not use the 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.

For vehicles 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).

When the brakes are applied, cruise control is turned off. For vehicles with an Allison or Hydra‐Matic 6‐speed automatic transmission, see “Grade Braking” under Tow/Haul Mode on page 9‑39
for an explanation of how cruise control interacts with the Range Selection Mode, tow/haul and grade braking systems. For vehicles with the StabiliTrak system that begins to limit wheel spin while you are using cruise control, the cruise control will automatically disengage. See StabiliTrak® System on page 9‑55. When road conditions allow the cruise control to be safely used again, it can be turned back on.

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[ (Cancel): Press to disengage cruise control without erasing the set speed from memory.

Setting Cruise Control If the cruise button is on when not in use, it could get bumped and go into cruise when not desired. Keep the cruise control switch off when cruise is not being used. The cruise control light on the instrument panel cluster will come on after the cruise control has been set to the desired speed. 1. Press I. 2. Get up to the desired speed. 3. Press the SET− button located

on the steering wheel and release it.

4. Take your foot off the

accelerator.

Resuming a Set Speed If the cruise control is set at a desired speed and then the brakes are applied, the cruise control is disengaged without erasing the set speed from memory. Once the vehicle speed reaches about 40 km/h (25 mph) or more, press the +RES button on the steering wheel. The vehicle returns to the previous set speed and stays there.

Increasing Speed While Using Cruise Control If the cruise control system is already activated, . Press and hold the +RES button

on the steering wheel until the desired speed is reached, then release it. To increase vehicle speed in small amounts, press the +RES button. Each time this is done, the vehicle goes about 1.6 km/h (1 mph) faster.

I (On/Off): Press to turn the system on or off. The indicator light is on when cruise control is on and turns off when cruise control is off. + RES (Resume/Accelerate): Press briefly to resume to a previously set speed, or press and hold to accelerate. SET − (Set/Coast): Press to set the speed and activate cruise control or make the vehicle decelerate.

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Driving and Operating

Reducing Speed While Using Cruise Control If the cruise control system is already activated, . Press and hold the SET– button

on the steering wheel until the desired lower speed is reached, then release it. To slow down in small amounts, press the SET– button on the steering wheel briefly. Each time this is done, the vehicle goes about 1.6 km/h (1 mph) slower.

Passing Another Vehicle While Using Cruise Control Use the accelerator pedal to increase the vehicle speed. When you take your foot off the pedal, the vehicle will slow down to the previous set cruise speed.

Using Cruise Control on Hills How well the cruise control works on hills depends on the vehicle speed, the load, and the steepness of the hills. When going up steep

hills, pressing the accelerator pedal may be necessary to maintain vehicle speed. While going downhill: . Vehicles with a four speed

automatic transmission may need to have the brakes applied or the transmission shifted to a lower gear to keep the speed down.

. Vehicles with a six speed

automatic transmission have a Cruise Grade Braking feature that may automatically shift to a lower gear to keep the speed down. It may be necessary to apply the brake or manually shift the transmission to a lower gear. The vehicle may shift to a higher gear when grade braking assistance is no longer required. Cruise Grade Braking is not available while in Range Selection Mode. This feature is

active when the exhaust brake is enabled (if equipped). See "Range Selection Mode" under Manual Mode on page 9‑38. When the brakes are manually applied the cruise control is disengaged.

Ending Cruise Control There are three ways to end cruise control:

To disengage cruise control; step lightly on the brake pedal.

. Press [ on the steering wheel.

To turn off the cruise control, press I on the steering wheel.

Erasing Speed Memory The cruise control set speed is erased from memory by pressing I or if the ignition is turned off.

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Object Detection Systems

Ultrasonic Parking Assist If available, the Ultrasonic Rear Parking Assist (URPA) system assists the driver with parking and avoiding objects while in R (Reverse). URPA operates at speeds less than 8 km/h (5 mph). The sensors on the rear bumper detect objects up to 2.5 m (8 ft) behind the vehicle, and at least 25 cm (10 in) off the ground. { WARNING

The URPA system does not detect pedestrians, bicyclists, animals, or objects below the bumper or that are too close or too far from the vehicle. To prevent injury, death, or vehicle damage, even with URPA, always (Continued)

WARNING (Continued)

check the area around the vehicle and check all mirrors before backing.

How the System Works URPA comes on automatically when the shift lever is moved into R (Reverse). A single tone sounds to indicate the system is working. URPA operates only at speeds less than 8 km/h (5 mph). An obstacle is indicated by audible beeps. The interval between the beeps becomes shorter as the vehicle gets closer to the obstacle. When the distance is less than 30 cm (12 in) the beeping is a continuous tone for five seconds. To be detected, objects must be at least 25 cm (10 in) off the ground and below tailgate level. Objects must also be within 2.5 m (8 ft) from

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the rear bumper. This distance may be less during warmer or humid weather. Turning the System On and Off The URPA system can be turned on and off using the rear park aid disable button located next to the radio.

The indicator light comes on when the system is disabled and turns off when the system is on. When the system is off, PARK ASSIST OFF displays on the Driver Information Center (DIC). The message disappears after a short period of time.

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Driving and Operating

URPA defaults to the on setting each time the vehicle is started. Notice: If you use URPA while the tailgate is lowered, it may not detect an object behind your vehicle, and you might back into the object and damage your vehicle. Always verify the tailgate is closed when using URPA or turn off URPA when driving with the tailgate lowered. When the System Does Not Seem to Work Properly The following messages may be displayed on the DIC: SERVICE PARK ASSIST: message occurs, take the vehicle to your dealer to repair the system.

If this

PARK ASST BLOCKED SEE OWNERS MANUAL: This message can occur under the following conditions:

The ultrasonic sensors are not clean. Keep the vehicle's rear bumper free of mud, dirt, snow, ice, and slush. For cleaning instructions, see Exterior Care on page 10‑98. The park assist sensors are covered by frost or ice. Frost or ice can form around and behind the sensors and may not always be seen; this can occur after washing the vehicle in cold weather. The message may not clear until the frost or ice has melted.

. A trailer was attached to the

vehicle, or an object was hanging out of the tailgate during the last drive cycle. Once the object is removed and the tailgate is raised, URPA will return to normal operation.

. A tow bar is attached to the

vehicle. The bumper is damaged. Take the vehicle to your dealer to repair the system.

. Other conditions, such as

vibrations from a jackhammer or the compression of air brakes on a very large truck, are affecting system performance.

Rear Vision Camera (RVC) If available, the Rear Vision Camera (RVC) system displays part of the scene behind the vehicle. { WARNING

The RVC system does not display pedestrians, bicyclists, animals, or any other object located outside the camera's field of view, below the bumper, or under the vehicle. Do not back the vehicle

(Continued)

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WARNING (Continued)

using only the RVC screen, such as during longer, higher speed backing maneuvers, or where there could be cross-traffic. Perceived distances may be different from actual distances. Failure to use proper care before backing may result in injury, death, or vehicle damage. Always check behind and around the vehicle before backing.

Vehicles without Navigation System The RVC system displays a view of the area behind the vehicle. When the vehicle is on and shifted into R (Reverse) the video image appears on the inside rearview mirror. The video image disappears after the vehicle is shifted out of R (Reverse).

Turning the RVC System On or Off To turn off the RVC system, press and hold z , located on the inside rearview mirror, until the left indicator light turns off. The RVC display is now disabled. To turn the RVC system on, press and hold z until the left indicator light comes on. The RVC system display will appear in the mirror. Vehicles with Navigation System The RVC system is designed to help the driver when backing up by displaying a view of the area behind the vehicle. When the vehicle is shifted into R (Reverse), the video image appears on the navigation screen. After a delay, the navigation screen displays the last screen after the vehicle is shifted out of R (Reverse).

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Turning the RVC System On or Off To turn the RVC system on or off: 1. Shift into P (Park). 2. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

3. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

4. Select the Video screen button. When the Video screen button is highlighted the RVC system is on.

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Driving and Operating

The delay after shifting out of R (Reverse) is approximately 10 seconds. The delay can be canceled by performing one of the following: . Pressing a hard key on the

navigation system.

. Shifting into P (Park). . Reaching a vehicle speed of

8 km/h (5 mph).

Adjusting the Brightness and Contrast of the Screen To adjust the brightness and contrast of the screen, press the MENU button while the RVC image is on the display. Any adjustments made will only affect the RVC screen. ] (Brightness): Touch the + (plus) or – (minus) screen buttons to increase or decrease the brightness of the screen.

_ (Contrast): Touch the + (plus) or – (minus) screen buttons to increase or decrease the contrast of the screen.

Symbols The navigation system may have a feature that allows for viewing parking assist symbols on the navigation screen while using the RVC. The Ultrasonic Rear Park Assist (URPA) system must not be disabled to use the caution symbols. If URPA has been disabled and the symbols have been turned on, the Rear Parking Assist Symbols Unavailable error message may display. See Ultrasonic Parking Assist on page 9‑61. The symbols appear near objects detected by the URPA system. The symbol may cover the object when viewing the navigation screen. To turn the symbols on or off: 1. Make sure that URPA has not

been disabled.

2. Shift into P (Park).

3. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

4. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

5. Touch the Symbols screen

button. The screen button will be highlighted when on.

Guidelines The RVC system has a guideline overlay that can help the driver align the vehicle when backing into a parking spot. If the vehicle has dual rear wheels, this feature will not be available. To turn the guidelines on or off: 1. Make sure that URPA has not

been disabled.

2. Shift into P (Park).

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3. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

4. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

5. Touch the Guidelines screen

button. The screen button will be highlighted when on.

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RVC Location

A. View displayed by the camera

The camera is located in the bezel for the tailgate handle. This shows the field of view that the camera provides.

A. View displayed by the camera B. Corners of the rear bumper

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Driving and Operating

Displayed images may be further or closer than they appear. The area displayed is limited and objects which are close to either corner of the bumper or under the bumper do not display.

Disconnecting the RVC The rear vision camera must be disconnected if the tailgate needs to be removed. To disconnect the camera: 1. Remove the license plate. 2. Disconnect the camera

connectors from the chassis harness, located behind the license plate, by pressing on the release tab on each connector.

A. Chassis harness connector B. Release tab C. Camera connector

3. Plug the two exposed chassis

harness connectors together to prevent contamination.

A. Chassis harness connector B. Release tab

4. Feed the wiring harness through

the pickup box, then plug the camera connectors together to prevent contamination.

5. Remove the tailgate. See

Tailgate on page 2‑10 for more information.

6. Reinstall the license plate.

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Reverse this procedure to reinstall the RVC and make sure the grommet and connection are secure. When the System Does Not Seem To Work Properly The RVC system might not work properly or display a clear image if:

The RVC is turned off. See “Turning the RVC System On or Off” earlier in this section. It is dark. The sun or the beam of headlamps is shining directly into the camera lens. Ice, snow, mud, or anything else builds up on the camera lens. Clean the lens, rinse it with water, and wipe it with a soft cloth.

The back of the vehicle is in an accident, the position and mounting angle of the camera can change or the camera can be affected. Be sure to have the camera and its position and mounting angle checked at your dealer.

The RVC system display in the rearview mirror may turn off or not appear as expected due to one of the following conditions. If this occurs the left indicator light on the mirror will flash. . A slow flash may indicate a loss

of video signal, or no video signal present during the reverse cycle.

. A fast flash may indicate that

the display has been on for the maximum allowable time during a reverse cycle, or the display has reached an Over Temperature limit.

The fast flash conditions are used to protect the video device from high temperature conditions. Once conditions return to normal the device will reset and the green indicator will stop flashing.

During any of these fault conditions, the display will be blank and the indicator will flash while the vehicle is in R (Reverse) or until the conditions return to normal. Press and hold z when the left indicator light is flashing to turn off the video display along with the left indicator light.

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Driving and Operating

Fuel For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax Diesel Supplement. For Vehicles with gasoline engines, please read this.

Gasoline Use of the recommended fuel is an important part of the proper maintenance of this vehicle. To help keep the engine clean and maintain optimum vehicle performance, we recommend the use of gasoline advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure gasoline meets enhanced detergency standards developed by auto companies. A list of marketers providing TOP TIER Detergent Gasoline can be found at www.toptiergas.com.

The eighth digit of the Vehicle Identification Number (VIN) shows the code letter or number that identifies the vehicle's engine. The VIN is at the top left of the instrument panel. See Vehicle Identification Number (VIN) on page 12‑1. Vehicles that have a FlexFuel badge and a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85).

See Fuel E85 (85% Ethanol) on page 9‑71. For all other vehicles, use only the unleaded gasoline described under Recommended Fuel on page 9‑68.

Recommended Fuel For all vehicles except those with the 6.2L V8 engine (VIN Code 2), use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, an audible knocking noise, commonly referred to as spark knock, might be heard when driving. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service.

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If the vehicle has the 6.2L V8 engine (VIN Code 2), use premium unleaded gasoline with a posted octane rating of 91 or higher. You can also use regular unleaded gasoline rated at 87 octane or higher, but the vehicle's acceleration could be slightly reduced, and a slight audible knocking noise, commonly referred to as spark knock, might be heard. If the octane is less than 87, you might notice a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you could damage the engine. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service.

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Gasoline Specifications (U.S. and Canada Only) At a minimum, gasoline should meet ASTM specification D 4814
in the United States or CAN/CGSB‐3.5 or 3.511 in Canada. Some gasolines contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT). We recommend against the use of gasolines containing MMT. See Fuel Additives on page 9‑70 for additional information.

California Fuel Requirements If the vehicle is certified to meet California Emissions Standards, it is designed to operate on fuels that meet California specifications. See the underhood emission control label. If this fuel is not available in states adopting California Emissions Standards, the vehicle will operate satisfactorily on fuels meeting federal specifications, but emission

control system performance might be affected. The malfunction indicator lamp could turn on and the vehicle might fail a smog‐check test. See Malfunction Indicator Lamp on page 5‑22. If this occurs, return to your authorized dealer for diagnosis. If it is determined that the condition is caused by the type of fuel used, repairs might not be covered by the vehicle warranty.

Fuels in Foreign Countries Never use leaded gasoline or any other fuel not recommended in the previous text on fuel. Costly repairs caused by use of improper fuel would not be covered by the vehicle warranty. To check the fuel availability, ask an auto club, or contact a major oil company that does business in the country where you will be driving.

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Driving and Operating

Fuel Additives To provide cleaner air, all gasolines in the United States are now required to contain additives that help prevent engine and fuel system deposits from forming, allowing the emission control system to work properly. In most cases, nothing should have to be added to the fuel. However, some gasolines contain only the minimum amount of additive required to meet U.S. Environmental Protection Agency regulations. To help keep fuel injectors and intake valves clean and avoid problems due to dirty injectors or valves, look for gasoline that is advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure gasoline meets enhanced detergency standards developed by the auto companies. A list of marketers providing TOP TIER Detergent Gasoline can be found at www.toptiergas.com.

For customers who do not use TOP TIER Detergent Gasoline regularly, one bottle of GM Fuel System Treatment PLUS, added to the fuel tank at every engine oil change, can help clean deposits from fuel injectors and intake valves. GM Fuel System Treatment PLUS is the only gasoline additive recommended by General Motors. It is available at your dealer. Gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines might be available in your area. We recommend that you use these gasolines, if they comply with the specifications described earlier. However, E85 (85% ethanol) and other fuels containing more than 15% ethanol must not be used in vehicles that were not designed for those fuels.

Notice: This vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic and rubber parts. That damage would not be covered under the vehicle warranty. Some gasolines that are not reformulated for low emissions can contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT); ask the attendant where you buy gasoline whether the fuel contains MMT. We recommend against the use of such gasolines. Fuels containing MMT can reduce spark plug life and affect emission control system performance. The malfunction indicator lamp might turn on. If this occurs, return to your dealer for service.

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At a minimum, E85 should meet ASTM Specification D 5798 or CGSB Specification 3.512. Filling the tank with fuel mixtures that do not meet ASTM or CGSB specifications can affect driveability and could cause the malfunction indicator lamp to come on. As the outside temperature approaches freezing, ethanol fuel distributors should supply winter grade ethanol, the same as with unleaded gasoline. It is best not to alternate repeatedly between gasoline and E85. If you do switch fuels, it is recommended that you add as much fuel as possible — do not add less than 11 L (3 gal) when refueling. You should drive the vehicle immediately after refueling for at least 11 km (7 mi) to allow the vehicle to adapt to the change in ethanol concentration.

E85 has less energy per liter (gallon) than gasoline, so you will need to refill the fuel tank more often when using E85 than when you are using gasoline. See Filling the Tank on page 9‑72. Notice: Some additives are not compatible with E85 fuel and can harm the vehicle's fuel system. Do not add anything to E85. Damage caused by additives would not be covered by the vehicle warranty. Notice: This vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic and rubber parts. That damage would not be covered under the vehicle warranty.

Fuel E85 (85% Ethanol) Vehicles that have a FlexFuel badge and a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85). For all other vehicles, use only the unleaded gasoline described under Recommended Fuel on page 9‑68. We encourage the use of E85 in vehicles that are designed to use it. The ethanol in E85 is a “renewable” fuel, meaning it is made from renewable sources such as corn and other crops. Many service stations will not have an 85% ethanol fuel (E85) pump available. The U.S. Department of Energy has an alternative fuels website (www.afdc.energy.gov/afdc/locator/ stations/) that can help you find E85 fuel. Those stations that do have E85 should have a label indicating ethanol content. Do not use the fuel if the ethanol content is greater than 85%.

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Driving and Operating

Filling the Tank If the vehicle has a diesel engine, see the Duramax diesel supplement for more information.

{ WARNING

Fuel vapor burns violently and a fuel fire can cause bad injuries. To help avoid injuries to you and others, read and follow all the instructions on the fuel pump island. Turn off the engine when refueling. Do not smoke near fuel or when refueling the vehicle. Do not use cellular phones. Keep sparks, flames, and smoking materials away from fuel. Do not leave the fuel pump unattended when refueling the vehicle. This is against the law in some places. Do not re-enter the vehicle while pumping fuel. Keep children away from the fuel pump; never let children pump fuel.

The tethered fuel cap is located behind a hinged fuel door on the driver side of the vehicle. Vehicles that have a FlexFuel badge and a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85). See Fuel E85 (85% Ethanol) on page 9‑71. To remove the fuel cap, turn it slowly counterclockwise. { WARNING Fuel can spray out on you if you open the fuel cap too quickly. If you spill fuel and then something ignites it, you could be badly burned. This spray can happen if the tank is nearly full, and is more likely in hot weather. Open the fuel cap slowly and wait for any hiss noise to stop. Then unscrew the cap all the way.

If the vehicle is a dual fuel tank chassis cab model, and it runs out of fuel, refuel the front fuel tank first to ensure a quick restart. Be careful not to spill fuel. Do not top off or overfill the tank and wait a few seconds after you have finished pumping before removing the nozzle. Clean fuel from painted surfaces as soon as possible. See Exterior Care on page 10‑98. When replacing the fuel cap, turn it clockwise until it clicks. It will require more effort to turn the fuel cap on the last turn as you tighten it. Make sure the cap is fully installed. The diagnostic system can determine if the fuel cap has been left off or improperly installed. This would allow fuel to evaporate into the atmosphere. See Malfunction Indicator Lamp on page 5‑22.

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WARNING (Continued)

. Bring the fill nozzle in contact

with the inside of the fill opening before operating the nozzle. Contact should be maintained until the filling is complete.

. Do not smoke while

pumping fuel.

. Do not use a cellular phone

while pumping fuel.

The TIGHTEN GAS CAP message displays on the Driver Information Center (DIC) if the fuel cap is not properly installed. See Fuel System Messages on page 5‑43 for more information.

{ WARNING If a fire starts while you are refueling, do not remove the nozzle. Shut off the flow of fuel by shutting off the pump or by notifying the station attendant. Leave the area immediately.

Notice: If a new fuel cap is needed, be sure to get the right type of cap from your dealer. The wrong type of fuel cap might not fit properly, might cause the malfunction indicator lamp to light, and could damage the fuel tank and emissions system. See Malfunction Indicator Lamp on page 5‑22.

Filling a Portable Fuel Container

{ WARNING

Never fill a portable fuel container while it is in the vehicle. Static electricity discharge from the container can ignite the fuel vapor. You can be badly burned and the vehicle damaged if this occurs. To help avoid injury to you and others:

. Dispense fuel only into

approved containers.

. Do not fill a container while it

is inside a vehicle, in a vehicle's trunk, pickup bed, or on any surface other than the ground.

(Continued)

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Driving and Operating

Towing

General Towing Information Only use towing equipment that has been designed for the vehicle. Contact your dealer or trailering dealer for assistance with preparing the vehicle for towing a trailer. See the following trailer towing information in this section:

For information on driving while towing a trailer, see “Driving Characteristics and Towing Tips.” For maximum vehicle and trailer weights, see “Trailer Towing.” For information on equipment to tow a trailer, see “Towing Equipment.”

For information on towing a disabled vehicle, see Towing the Vehicle on page 10‑93. For information on towing the vehicle behind another

vehicle such as a motor home, see Recreational Vehicle Towing on page 10‑93.

Driving Characteristics and Towing Tips

Pulling a Trailer Important points for pulling a trailer:

There are many different laws, including speed limit restrictions, having to do with trailering. Make sure the rig will be legal, not only where you live but also where you will be driving. A good source for this information can be state or provincial police.

. Consider using a sway control.

See “Hitches” under Towing Equipment on page 9‑94.

. Do not tow a trailer at all during the first 800 km (500 miles) the new vehicle is driven. The engine, axle, or other parts could be damaged.

. During the first 800 km

(500 miles) that a trailer is towed, do not drive over 80 km/h (50 mph) and do not make starts at full throttle. This helps the engine and other parts of the vehicle wear in at the heavier loads.

. Vehicles can tow in D (Drive).

Shift the transmission to a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions.

Important considerations that have to do with weight: . Weight of the trailer . Weight of the trailer tongue . Weight on the vehicle's tires . Weight of the trailering

combination

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Driving with a Trailer

{ WARNING

When towing a trailer, exhaust gases may collect at the rear of the vehicle and enter if the liftgate, trunk/hatch, or rear-most window is open. Engine exhaust contains Carbon Monoxide (CO) which cannot be seen or smelled. It can cause unconsciousness and even death. To maximize safety when towing a trailer:

. Have the exhaust system

inspected for leaks and make necessary repairs before starting a trip.

. Never drive with the liftgate,

trunk/hatch, or rear-most window open.

(Continued)

Driving and Operating

9-75

lamps, tires, and mirrors. If the trailer has electric brakes, start the combination moving and then apply the trailer brake controller by hand to be sure the brakes work. During the trip, check occasionally to be sure that the load is secure and the lamps and any trailer brakes still work. Following Distance Stay at least twice as far behind the vehicle ahead as you would when driving the vehicle without a trailer. This can help to avoid heavy braking and sudden turns. Passing More passing distance is needed when towing a trailer. The combination will not accelerate as quickly and is longer so it is necessary to go much farther beyond the passed vehicle before returning to the lane.

WARNING (Continued)

. Fully open the air outlets on

or under the instrument panel.

. Adjust the Climate Control

system to a setting that brings in only outside air and set the fan speed to the highest setting. See Climate Control System in the Index.

For more information about Carbon Monoxide, see Engine Exhaust on page 9‑33.

Towing a trailer requires a certain amount of experience. The combination you are driving is longer and not as responsive as the vehicle itself. Get acquainted with the handling and braking of the rig before setting out for the open road. Before starting, check all trailer hitch parts and attachments, safety chains, electrical connectors,

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Black plate (76,1)

9-76

Driving and Operating

Backing Up Hold the bottom of the steering wheel with one hand. To move the trailer to the left, move that hand to the left. To move the trailer to the right, move your hand to the right. Always back up slowly and, if possible, have someone guide you. Making Turns Notice: Making very sharp turns while trailering could cause the trailer to come in contact with the vehicle. The vehicle could be damaged. Avoid making very sharp turns while trailering. When turning with a trailer, make wider turns than normal. Do this so the trailer will not strike soft shoulders, curbs, road signs, trees, or other objects. Avoid jerky or sudden maneuvers. Signal well in advance.

If the trailer turn signal bulbs burn out, the arrows on the instrument panel will still flash for turns. It is important to check occasionally to be sure the trailer bulbs are still working. Driving on Grades Reduce speed and shift to a lower gear before starting down a long or steep downgrade. If the transmission is not shifted down, the brakes might get hot and no longer work well. Vehicles can tow in D (Drive). Shift the transmission to a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions. The Tow/Haul Mode may be used if the transmission shifts too often. See Tow/Haul Mode on page 9‑39. When towing at high altitude on steep uphill grades, consider the following: Engine coolant will boil at a lower temperature than at normal altitudes. If the engine is turned off

immediately after towing at high altitude on steep uphill grades, the vehicle may show signs similar to engine overheating. To avoid this, let the engine run while parked, preferably on level ground, with the automatic transmission in P (Park) for a few minutes before turning the engine off. If the overheat warning comes on, see Engine Overheating on page 10‑22. Parking on Hills

{ WARNING

Parking the vehicle on a hill with the trailer attached can be dangerous. If something goes wrong, the rig could start to move. People can be injured, and both the vehicle and the trailer can be damaged. When possible, always park the rig on a flat surface.

GMC Sierra Owner Manual - 2012 - CRC - 11/15/11

Black plate (77,1)

If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into the curb if facing downhill or into traffic if facing uphill.

2. Have someone place chocks

under the trailer wheels.

3. When the wheel chocks are in

place, release the regular brakes until the chocks absorb the load.

4. Reapply the brake pedal. Then

5.

apply the parking brake and shift into P (Park). If the vehicle is four-wheel-drive, be sure the transfer case is in a drive gear and not in N (Neutral).

6. Release the brake pedal.

{ WARNING

It can be dangerous to get out of the vehicle if the shift lever is not fully in P (Park) with the parking brake firmly set. The vehicle can roll. If the engine has been left running, the vehicle can move suddenly. You or others could be injured. To be sure the vehicle will not move, even when on fairly level ground, use the steps that follow. Always put the shift lever fully in P (Park) with the parking brake firmly set.

(Continued)

Driving and Operating

9-77

WARNING (Continued)

If the transfer case on a four-wheel-drive vehicle is in N (Neutral), the vehicle will be free to roll, even if the shift lever is in P (Park). Be sure the transfer case is in a drive gear — not in N (Neutral).

Leaving After Parking on a Hill 1. Apply and hold the brake pedal. 2. Start the engine. 3. Shift into a gear. 4. Release the parking brake. 5. Let up on the brake pedal. 6. Drive slowly until the trailer is

clear of the chocks.

7. Stop and have someone pick up

and store the chocks.

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Black plate (78,1)

9-78

Driving and Operating

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 for more information. If the vehicle is a hybrid, see the hybrid supplement for more information. Do not tow a trailer during break-in. See New Vehicle Break-In on page 9‑25 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.

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Black plate (79,1)

Driving and Operating

9-79

Notice: 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. To identify the trailering capacity of the vehicle, read the information in “Weight of the Trailer” later in this section. 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. So please 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 tongue weight the vehicle can carry. See “Weight of the Trailer Tongue” later in this section for more information.

Trailer weight rating (TWR) 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. For kingpin weight and trailer tongue weight information, see “Weight of the Trailer Tongue” later in this section.

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Black plate (80,1)

9-80

Driving and Operating

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.

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

1500 Series 2WD Regular Cab Standard Box

4.3L V6 (b) 4.3L V6 — With Automatic Transmission (b) 4.3L V6 — With Manual Transmission (b) 4.8L V8 (b) 4.8L V8 (b) 5.3L LMG V8 (b) 5.3L LMG V8, K5L HD Cooling Pkg 5.3L LMG V8 K5L HD Cooling Pkg

3.23

3.73

3.73

3.23
3.73
3.08

3.08

3.42

2 177 kg (4,800 lbs)

4 309 kg (9,500 lbs)

2 449 kg (5,400 lbs)

4 536 kg (10,000 lbs)

1 860 kg (4,100 lbs)

3 938 kg (8,683 lbs)

2 132 kg (4,700 lbs) 3 266 kg (7,200 lbs) 2 994 kg (6,600 lbs)

4 309 kg (9,500 lbs) 5 443 kg (12,000 lbs) 5 216 kg (11,500 lbs)

3 357 kg (7,400 lbs)

5 534 kg (12,200 lbs)

4 128 kg (9,100 lbs)

6 350 kg (14,000 lbs)

1500 Series 2WD Extended Cab Standard Box

4.3L V6 (b) 4.8L V8 (b) 4.8L V8 (b)

3.23
3.23
3.73

1 996 kg (4,400 lbs) 2 132 kg (4,700 lbs) 3 039 kg (6,700 lbs)

4 309 kg (9,500 lbs) 4 536 kg (10,000 lbs) 5 443 kg (12,000 lbs)

GMC Sierra Owner Manual - 2012 - CRC - 11/15/11

Black plate (81,1)

Driving and Operating

9-81

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg (b) 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer 6.2L V8 K5L HD Cooling Pkg — Conventional Trailer 6.2L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer 6.2L V8 NHT Max Trailering Pkg — Conventional Trailer 6.2L V8 NHT Max Trailering Pkg — Fifth-Wheel Trailer

1500 Series 2WD Crew Cab Short Box (b)

4.8L V8
4.8L V8
5.3L V8 (LMG)

3.08
3.08

3.42

3.42

3.42

3.42

3.73

3.73

3.23
3.73
3.08

2 812 kg (6,200 lbs) 3 130 kg (6,900 lbs)

5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 400 kg (9,700 lbs)

6 804 kg (15,000 lbs)

4 264 kg (9,400 lbs)

6 804 kg (15,000 lbs)

4 400 kg (9,700 lbs)

6 804 kg (15,000 lbs)

4 264 kg (9,400 lbs)

6 804 kg (15,000 lbs)

4 853 kg (10,700 lbs)

7 257 kg (16,000 lbs)

4 808 kg (10,600 lbs)

7 257 kg (16,000 lbs)

2 132 kg (4,700 lbs) 3 039 kg (6,700 lbs) 2 812 kg (6,200 lbs)

4 536 kg (10,000 lbs) 5 443 kg (12,000 lbs) 5 216 kg (11,500 lbs)

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Black plate (82,1)

9-82

Driving and Operating

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

5.3L V8 (LMG) K5L HD Cooling Pkg 5.3L V8 (LC9) XFE 5.3L V8 (LMG) K5L HD Cooling Pkg 6.2L V8 K5L HD Cooling Pkg 6.2L V8 NHT Max Trailering Pkg

1500 Series 2WD Regular Cab Long Box

4.3L V6 (b) 4.3L V6 (b) 4.8L V8 (b) 4.8L V8 (b) 5.3L V8
5.3L V8 K5L HD Cooling Pkg 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer

3.08

3.08

3.42

3.42
3.73

3.23
3.73
3.23
3.73
3.08
3.08

3.42

3.42

3 130 kg (6,900 lbs)

5 534 kg (12,200 lbs)

3 175 kg (7,000 lbs)

5 534 kg (12,200 lbs)

4 355 kg (9,600 lbs)

6 804 kg (15,000 lbs)

4 400 kg (9,700 lbs) 4 808 kg (10,600 lbs)

6 804 kg (15,000 lbs) 7 257 kg (16,000 lbs)

2 132 kg (4,700 lbs) 2 359 kg (5,200 lbs) 2 313 kg (5,100 lbs) 3 221 kg (7,100 lbs) 2 948 kg (6,500 lbs) 3 266 kg (7,200 lbs)

4 309 kg (9,500 lbs) 4 536 kg (10,000 lbs) 4 536 kg (10,000 lbs) 5 443 kg (12,000 lbs) 5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 536 kg (10,000 lbs)

6 804 kg (15,000 lbs)

4 037 kg (8,900 lbs)

6 804 kg (15,000 lbs)

GMC Sierra Owner Manual - 2012 - CRC - 11/15/11

Black plate (83,1)

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

Driving and Operating

9-83

1500 Series 2WD Extended Cab Long Box

5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg (b) 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer

1500 Series 4WD Regular Cab Standard Box

4.3L V6 (b) 4.8L V8 (b) 5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer

3.08
3.08

3.42

3.42

3.73
3.42
3.08
3.08

3.42

3.42

2 722 kg (6,000 lbs) 3 039 kg (6,700 lbs)

5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 309 kg (9,500 lbs)

6 804 kg (15,000 lbs)

4 082 kg (9,000 lbs)

6 804 kg (15,000 lbs)

2 313 kg (5,100 lbs) 2 722 kg (6,000 lbs) 2 903 kg (6,400 lbs) 3 221 kg (7,100 lbs)

4 536 kg (10,000 lbs) 4 990 kg (11,000 lbs) 5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 037 kg (8,900 lbs)

6 350 kg (14,000 lbs)

3 719 kg (8,200 lbs)

6 350 kg (14,000 lbs)

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Black plate (84,1)

9-84

Driving and Operating

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

1500 Series 4WD Extended Cab Standard Box

4.8L V8 (b) 5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg (b) 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer 6.2L V8 K5L HD Cooling Pkg — Conventional Trailer 6.2L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer 6.2L V8 NHT Max Trailering Pkg — Conventional Trailer 6.2L V8 NHT Max Trailering Pkg — Fifth-Wheel Trailer

1500 Series 4WD Crew Cab Short Box (b)

4.8L V8
5.3L V8

3.42
3.08
3.08

3.42

3.42

3.42

3.42

3.73

3.73

3.42
3.08

2 495 kg (5,500 lbs) 2 767 kg (6,100 lbs) 3 084 kg (6,800 lbs)

4 990 kg (11,000 lbs) 5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 354 kg (9,600 lbs)

6 804 kg (15,000 lbs)

4 354 kg (9,600 lbs)

6 804 kg (15,000 lbs)

4 264 kg (9,400 lbs)

6 804 kg (15,000 lbs)

4 128 kg (9,100 lbs)

6 804 kg (15,000 lbs)

4 717 kg (10,400 lbs)

7 257 kg (16,000 lbs)

4 672 kg (10,300 lbs)

7 257 kg (16,000 lbs)

2 495 kg (5,500 lbs) 2 722 kg (6,000 lbs)

4 990 kg (11,000 lbs) 5 216 kg (11,500 lbs)

GMC Sierra Owner Manual - 2012 - CRC - 11/15/11

Black plate (85,1)

Driving and Operating

9-85

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

5.3L V8 K5L HD Cooling Pkg 5.3L V8 K5L HD Cooling Pkg 6.2L V8 K5L HD Cooling Pkg 6.2L V8 NHT Max Trailering Pkg

1500 Series 4WD Regular Cab Long Box

4.3L V6 (b) 4.8L V8 (b) 5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg 5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer

1500 Series 4WD Extended Cab Long Box

5.3L V8 (b) 5.3L V8 K5L HD Cooling Pkg (b)

3.08
3.42
3.42
3.73

3.73
3.42
3.08
3.08

3.42

3.42

3.08
3.08

3 039 kg (6,700 lbs) 4 309 kg (9,500 lbs) 4 264 kg (9,400 lbs) 4 717 kg (10,400 lbs)

2 223 kg (4,900 lbs) 2 631 kg (5,800 lbs) 2 858 kg (6,300 lbs) 3 175 kg (7,000 lbs)

5 534 kg (12,200 lbs) 6 804 kg (15,000 lbs) 6 804 kg (15,000 lbs) 7 257 kg (16,000 lbs)

4 536 kg (10,000 lbs) 4 990 kg (11,000 lbs) 5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

4 445 kg (9,800 lbs)

6 804 kg (15,000 lbs)

4 400 kg (9,700 lbs)

6 804 kg (15,000 lbs)

2 631 kg (5,800 lbs) 2 948 kg (6,500 lbs)

5 216 kg (11,500 lbs) 5 534 kg (12,200 lbs)

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Black plate (86,1)

9-86

Driving and Operating

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

5.3L V8 K5L HD Cooling Pkg — Conventional Trailer 5.3L V8 K5L HD Cooling Pkg — Fifth-Wheel Trailer

3.42

3.42

4 218 kg (9,300 lbs)

6 804 kg (15,000 lbs)

3 674 kg (8,100 lbs)

6 804 kg (15,000 lbs)

2500 Series 2WD Extended Cab Standard Box HD 3.73
4.10
4.10

6.0L V8
6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer

2500 Series 2WD Crew Cab Standard Box HD

6.0L V8
6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer

2500 Series 2WD Regular Cab Long Box HD

6.0L V8
6.0L V8 — Payload Performance Pkg (UB7) 6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer

3.73
4.10
4.10

3.73

3.73

4.10
4.10

4 445 kg (9,800 lbs) 5 897 kg (13,000 lbs) 6 486 kg (14,300 lbs)

7 257 kg (16,000 lbs) 9 299 kg (20,500 lbs) 9 299 kg (20,500 lbs)

4 400 kg (9,700 lbs) 5 897 kg (13,000 lbs) 6 441 kg (14,200 lbs)

7 257 kg (16,000 lbs) 9 299 kg (20,500 lbs) 9 299 kg (20,500 lbs)

4 627 kg (10,200 lbs)

7 257 kg (16,000 lbs)

4 536 kg (10,000 lbs)

7 257 kg (16,000 lbs)

5 897 kg (13,000 lbs) 6 668 kg (14,700 lbs)

9 299 kg (20,500 lbs) 9 299 kg (20,500 lbs)

GMC Sierra Owner Manual - 2012 - CRC - 11/15/11

Black plate (87,1)

Driving and Operating

9-87

Vehicle

Axle Ratio

Maximum Trailer Weight

GCWR (a)

2500 Series 2WD Extended Cab Long Box HD

6.0L V8
6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer

3.73
4.10
4.10

4 400 kg (9,700 lbs) 5 897 kg (13,000 lbs) 6 441 kg (14,200 lbs)

7 257 kg (16,000 lbs) 9 299 kg (20,500 lbs) 9 299 kg (20,500 lbs)

2500 Series 2WD Crew Cab Long Box HD

6.0L V8
6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer

3.73
4.10
4.10
2500 Series 4WD Extended Cab Standard Box HD 3.73
4.10
4.10

6.0L V8
6.0L V8 — Conventional Trailer 6.0L V8 — Fifth-Wheel Trailer