2011 GMC Sierra Owners Manual

Transfer Case

When to Check Lubricant Refer to Scheduled Maintenance on page 11‑2 to determine when to check the lubricant.

How to Check Lubricant

Electric Shift Transfer Case

A. Fill Plug B. Drain Plug

GMC Sierra Owner Manual - 2011

Black plate (35,1)

Vehicle Care

10-35

If the level is below the bottom of the fill plug hole, located on the transfer case, some lubricant will need to be added. Add enough lubricant to raise the level to the bottom of the fill plug hole. Use care not to overtighten the plug.

When to Change Lubricant Refer to Scheduled Maintenance on page 11‑2 to determine how often to change the lubricant.

What to Use Refer to Recommended Fluids and Lubricants on page 11‑8 to determine what kind of lubricant to use.

Manual Shift Transfer Case

Active Transfer Case

A. Fill Plug B. Drain Plug

A. Fill Plug B. Drain Plug To get an accurate reading, the vehicle should be on a level surface.

GMC Sierra Owner Manual - 2011

Black plate (36,1)

10-36

Vehicle Care

Front Axle

When to Check and Change Lubricant It is not necessary to regularly check front axle fluid unless a leak is suspected, or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired.

How to Check Lubricant To get an accurate reading, the vehicle should be on a level surface.

1500 Series

All Except 1500 Series

A. Fill Plug B. Drain Plug

A. Fill Plug B. Drain Plug . When the differential is cold,

add enough lubricant to raise the level from 0 mm (0 in) to 3.2 mm (1/8 in) below the fill plug hole.

. When the differential is at

operating temperature (warm), add enough lubricant to raise the level to the bottom of the fill plug hole.

GMC Sierra Owner Manual - 2011

Black plate (37,1)

Vehicle Care

10-37

What to Use Refer to Recommended Fluids and Lubricants on page 11‑8 to determine what kind of lubricant to use.

Rear Axle

When to Check Lubricant It is not necessary to regularly check rear axle fluid unless a leak is suspected or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired. All axle assemblies are filled by volume of fluid during production. They are not filled to reach a certain level. When checking the fluid level on any axle, variations in the readings can be caused by factory fill differences between the minimum and the maximum fluid volume. Also, if a vehicle has just been driven before checking the fluid level, it may appear lower than

normal because fluid has traveled out along the axle tubes and has not drained back to the sump area. Therefore, a reading taken five minutes after the vehicle has been driven will appear to have a lower fluid level than a vehicle that has been stationary for an hour or two. Remember that the rear axle assembly must be supported to get a true reading. How to Check Lubricant

2500HD with 6.0 L

All Other Series and Engines

To get an accurate reading, the vehicle should be on a level surface.

For all 4.3 L, 4.8 L and 5.3 L 1500 Series applications, the proper level is 1.0 mm to 19.0 mm (0.04 in to 0.7 in) below the bottom of the fill hole, located on the rear axle. Add only enough fluid to reach the proper level.

GMC Sierra Owner Manual - 2011

Black plate (38,1)

10-38

Vehicle Care

For all 6.0 L and 6.2 L 1500
Series applications, the proper level is from 15 mm to 40 mm (0.6 in to 1.6 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level. For all 6.0 L 2500HD Series applications, the proper level is from 0 mm to 13 mm (0 to 0.5 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level. For all 6.6 L Duramax Diesel 2500HD Series applications and all 3500 Series applications, the proper level is from 17 mm to 21 mm (0.6 in to 0.8 in) below the bottom of the fill plug hole, located on the rear axle. Add only enough fluid to reach the proper level.

What to Use Refer to Recommended Fluids and Lubricants on page 11‑8 to determine what kind of lubricant to use.

Noise Control System The following information relates to compliance with federal noise emission standards for vehicles with a Gross Vehicle Weight Rating (GVWR) of more than 4 536 kg (10,000 lbs). The Scheduled Maintenance on page 11‑2 provides information on maintaining the noise control system to minimize degradation of the noise emission control system during the life of your vehicle. The noise control system warranty is given in your warranty booklet.

These standards apply only to vehicles sold in the United States. Federal law prohibits the following acts or the causing thereof: 1. The removal or rendering inoperative by any person, other than for purposes of maintenance, repair or replacement, of any device or element of design incorporated into any new vehicle for the purpose of noise control, prior to its sale or delivery to the ultimate purchaser or while it is in use; or

2. The use of the vehicle after

such device or element of design has been removed or rendered inoperative by any person.

GMC Sierra Owner Manual - 2011

Black plate (39,1)

Vehicle Care

10-39

2. Firmly apply both the parking brake and the regular brake. See Parking Brake on page 9‑69. Do not use the accelerator pedal, and be ready to turn off the engine immediately if it starts.

3. Try to start the engine in each gear. The vehicle should start only in P (Park) or N (Neutral). If the vehicle starts in any other position, contact your dealer for service.

Exhaust: . Removal of the muffler and/or

resonator.

. Removal of the exhaust pipes

and exhaust pipe clamps.

Starter Switch Check

{ WARNING When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured.

1. Before starting this check, be

sure there is enough room around the vehicle.

Among those acts presumed to constitute tampering are the acts listed below.

Insulation: Removal of the noise shields or any underhood insulation.

Engine: Removal or rendering engine speed governor, if the vehicle has one, inoperative so as to allow engine speed to exceed manufacturer specifications.

Fan and Drive: . Removal of fan clutch, if the

vehicle has one, or rendering clutch inoperative.

. Removal of the fan shroud, if the

vehicle has one.

Air Intake: . Removal of the air cleaner

silencer.

. Modification of the air cleaner.

GMC Sierra Owner Manual - 2011

Black plate (40,1)

10-40

Vehicle Care

Automatic Transmission Shift Lock Control Function Check

{ WARNING When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured.

1. Before starting this check, be

sure there is enough room around the vehicle. It should be parked on a level surface.

2. Firmly apply the parking

brake. See Parking Brake on page 9‑69. Be ready to apply the regular brake immediately if the vehicle begins to move.

3. With the engine off, turn the

ignition on, but do not start the engine. Without applying the regular brake, try to move the shift lever out of P (Park) with normal effort. If the shift lever moves out of P (Park), contact your dealer for service.

Ignition Transmission Lock Check While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position.

The ignition should turn to LOCK/OFF only when the shift lever is in P (Park). The ignition key should come out only in LOCK/OFF.

Contact your dealer if service is required.

Park Brake and P (Park) Mechanism Check { WARNING

When you are doing this check, the vehicle could begin to move. You or others could be injured and property could be damaged. Make sure there is room in front of the vehicle in case it begins to roll. Be ready to apply the regular brake at once should the vehicle begin to move.

GMC Sierra Owner Manual - 2011

Black plate (41,1)

Park on a fairly steep hill, with the vehicle facing downhill. Keeping your foot on the regular brake, set the parking brake.

To check the parking brake's holding ability: With the engine running and the transmission in N (Neutral), slowly remove foot pressure from the regular brake pedal. Do this until the vehicle is held by the parking brake only. To check the P (Park) mechanism's holding ability: With the engine running, shift to P (Park). Then release the parking brake followed by the regular brake.

Contact your dealer if service is required.

Wiper Blade Replacement Windshield wiper blades should be inspected for wear or cracking. See Scheduled Maintenance on page 11‑2 for more information on wiper blade inspection. Replacement blades come in different types and are removed in different ways. To remove the wiper blade: 1. Pull the windshield wiper arm

connector away from the windshield.

2. Squeeze the grooved areas on each side of the blade, and turn the blade assembly away from the arm connector.

Vehicle Care

10-41

3.

Install the new blade onto the arm connector and make sure the grooved areas are fully set in the locked position.

For the proper type and size, see Maintenance Replacement Parts on page 11‑11.

Glass Replacement If the windshield or front side glass must be replaced, see your dealer to determine the correct replacement glass.

GMC Sierra Owner Manual - 2011

Black plate (42,1)

10-42

Vehicle Care

Headlamp Aiming The vehicle has a visual optical headlamp aiming system. The aim of the headlamps has been preset at the factory and should need no further adjustment. However, if the vehicle is damaged in a crash, the aim of the headlamps may be affected and adjustment may be necessary. If oncoming vehicles flash their high beams at you, this may mean the vertical aim of the headlamps needs to be adjusted. It is recommended that the vehicle be taken to the dealer for service if the headlamps need to be adjusted. It is possible, however, to re-aim the headlamps as described.

The vehicle should: . Be placed so the headlamps

are 7.6 m (25 ft) from a light‐colored wall.

. Have all four tires on a level surface which is level all the way to the wall.

. Be placed so it is perpendicular

to the wall.

. Not have any snow, ice, or mud

on it.

. Be fully assembled and all other

work stopped while headlamp aiming is being performed. . Be loaded with a full tank of fuel and one person or 75 kg (160 lbs) sitting on the driver seat.

. Have the tires properly inflated. . Have the spare tire in its proper

location in the vehicle.

Headlamp aiming is done with the vehicle's low-beam headlamps. The high-beam headlamps will be correctly aimed if the low-beam headlamps are aimed properly. To adjust the vertical aim: 1. Open the hood. See Hood on

page 10‑5.

2. Locate the aim dot on the lens of

the low‐beam headlamp.

3. Record the distance from the ground to the aim dot on the low‐beam headlamp.

GMC Sierra Owner Manual - 2011

Black plate (43,1)

Vehicle Care

10-43

Notice: Do not cover a headlamp to improve beam cut-off when aiming. Covering a headlamp may cause excessive heat build-up which may cause damage to the headlamp. 6. Turn on the low-beam

headlamps and place a piece of cardboard or equivalent in front of the headlamp not being adjusted. This allows only the beam of light from the headlamp being adjusted to be seen on the flat surface.

4. At a wall, measure from the

ground upward (A) to the recorded distance from Step 3 and mark it.

5. Draw or tape a horizontal line (B)

on the wall the width of the vehicle at the height of the mark in Step 4.

7. Locate the vertical headlamp

aiming screws, which are under the hood near each headlamp assembly. The adjustment screw can be turned with an E8 Torx® socket.

8. Turn the vertical aiming screw

until the headlamp beam is aimed to the horizontal tape line. Turn it clockwise or counterclockwise to raise or lower the angle of the beam.

GMC Sierra Owner Manual - 2011

Black plate (44,1)

10-44

Vehicle Care

9. Make sure that the light from the

headlamp is positioned at the bottom edge of the horizontal tape line. The lamp on the left (A) shows the correct headlamp aim. The lamp on the right (B) shows the incorrect headlamp aim.

10. Repeat Steps 7 through 9 for

the opposite headlamp.

Headlamps To replace one of these bulbs: 1. Open the hood. See Hood on

2.

page 10‑5
If you are replacing the bulb on the passenger side, remove the Engine Air Cleaner cover. See Engine Air Cleaner/Filter on page 10‑19 for more information.

3. Reach in and access the bulb sockets from inside the engine compartment.

Bulb Replacement For the proper type of replacement bulbs, see Replacement Bulbs on page 10‑48. For any bulb‐changing procedure not listed in this section, contact your dealer.

Halogen Bulbs

{ WARNING

Halogen bulbs have pressurized gas inside and can burst if you drop or scratch the bulb. You or others could be injured. Be sure to read and follow the instructions on the bulb package.

GMC Sierra Owner Manual - 2011

Black plate (45,1)

4. Turn the bulb socket

counterclockwise to remove it from the headlamp assembly and pull it straight out.

5. Unplug the electrical connector

from the old bulb by releasing the clips on the bulb socket.

6. Replace it with a new bulb

socket.

7. Plug in the electrical connector

to the new bulb socket.

8. Reinstall the new bulb socket

into the headlamp assembly and turn it clockwise to secure.

Vehicle Care

10-45

Pick-Up Box Identification and Fender Marker Lamps The pick-up box identification lamps are LEDs. For replacement of the LED lighting assembly contact your dealer. To replace a pickup box fender marker lamp bulb: 1. Press the tab from the back to

remove the lamp.

2. Turn the bulb socket

counterclockwise to remove from the lamp assembly.

3. Gently pry the bulb from the

socket. Install the new bulb in socket.

4. 5. Reinstall socket into lamp

assembly.

6. Reinstall the lamp assembly.

A. Sidemarker Lamp B. Low Beam Headlamp C. High Beam Headlamp D. Turn Signal Lamp/

Parking Lamp

GMC Sierra Owner Manual - 2011

Black plate (46,1)

10-46

Vehicle Care

Taillamps (Chassis Cab Models)

A. Backup Lamp B. Stoplamp/Taillamp/Turn

Signal Lamp

Taillamps, Turn Signal, Stoplamps, and Back-Up Lamps To replace one of these bulbs: 1. Open the tailgate. See Tailgate

on page 2‑10 for more information.

To replace one of these bulbs: 1. Remove the four screws. 2. Lift the lens off the lamp

assembly.

3. Turn the old bulb

counterclockwise and pull the it straight out from the socket. Install a new bulb into the socket, turn it clockwise, and press it in until it is tight.

4.

5. Reinstall the lens and the four

screws.

2. Remove the two rear lamp assembly screws near the tailgate latch strikerpost and pull rearward until disengaging the two outer pins on the taillamp assembly from the vehicle.

GMC Sierra Owner Manual - 2011

Black plate (47,1)

Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp To replace one of these bulbs:

1. Remove the two screws and lift

off the lamp assembly.

Vehicle Care

10-47

2. On the reverse side of the lamp

assembly, remove the bulb socket by turning it one quarter turn counterclockwise and pull it straight out.

3. Remove the bulb by pulling it

4.

5.

straight out of the socket. Install the bulb by pushing the bulb straight into the socket. Install the bulb socket into the lamp asembly by turning it one quarter turn clockwise.

6. Reinstall the lamp assembly and

tighten the screws.

A. Cargo Lamp B. Center High-Mounted

Stoplamp (CHMSL) Bulb

A. Stoplamp/Turn Signal/Taillamp B. Back-up Lamp C. Sidemarker Lamp 3. Turn the bulb socket

counterclockwise to remove it from the taillamp assembly. 4. Pull the old bulb straight out

from the socket.

5. Press a new bulb into the socket

and turn the socket clockwise into the taillamp assembly.

6. Reinstall the taillamp assembly.

GMC Sierra Owner Manual - 2011

Black plate (48,1)

10-48

Vehicle Care

License Plate Lamp To replace one of these bulbs: 1. Reach under the rear bumper for

the bulb socket.

2. Turn the bulb socket

counterclockwise and pull the bulb socket out of the lamp assembly.

3. Pull the old bulb straight out

from the bulb socket. Install the new bulb.

4. 5. Reverse Steps 1 and 2 to reinstall the bulb socket.

Replacement Bulbs

Exterior Lamp

Back-up Lamp Back-up Lamp* Cargo Lamp and Center High-Mounted Stoplamp (CHMSL) Fender Marker High-Beam Headlamp Low-Beam Headlamp

Bulb

Number

921
1156

912

W5WLL

9005

H11

Exterior Lamp

License Plate Lamp Stoplamp/Taillamp/ Turn Signal Lamp Sidemarker Lamp Stoplamp/Turn Signal Lamp/ Taillamp* * Chassis Cab Models

Bulb

Number

168

3047K

194

1157

For replacement bulbs not listed here, contact your dealer.

GMC Sierra Owner Manual - 2011

Black plate (49,1)

Vehicle Care

10-49

Replace a bad fuse with a new one of the identical size and rating. If there is a problem on the road and a fuse needs to be replaced, the same amperage fuse can be borrowed. Choose some feature of the vehicle that is not needed to use and replace it as soon as possible. Headlamp Wiring An electrical overload may cause the lamps to go on and off, or in some cases to remain off. Have the headlamp wiring checked right away if the lamps go on and off or remain off.

Windshield Wipers If the wiper motor overheats due to heavy snow or ice, the windshield wipers will stop until the motor cools and will then restart. Although the circuit is protected from electrical overload, overload due to heavy snow or ice may cause wiper linkage damage. Always clear ice and heavy snow from the windshield before using the windshield wipers. If the overload is caused by an electrical problem and not snow or ice, be sure to get it fixed.

Electrical System

Electrical System Overload The vehicle has fuses and circuit breakers to protect against an electrical system overload. When the current electrical load is too heavy, the circuit breaker opens and closes, protecting the circuit until the current load returns to normal or the problem is fixed. This greatly reduces the chance of circuit overload and fire caused by electrical problems. Fuses and circuit breakers protect the following in the vehicle: . Headlamp Wiring . Windshield Wiper Motor . Power Windows and Other

Power Accessories

GMC Sierra Owner Manual - 2011

Black plate (50,1)

10-50

Vehicle Care

Fuses and Circuit Breakers If the vehicle is a hybrid, see the hybrid supplement for more information. The wiring circuits in the vehicle are protected from short circuits by a combination of fuses, circuit breakers and fusible thermal links. This greatly reduces the chance of fires caused by electrical problems. Look at the silver-colored band inside the fuse. If the band is broken or melted, replace the fuse. Be sure you replace a bad fuse with a new one of the identical size and rating. If you ever have a problem on the road and don't have a spare fuse, you can borrow one that has the same amperage. Just pick some

feature of your vehicle that you can get along without – like the radio or cigarette lighter – and use its fuse, if it is the correct amperage. Replace it as soon as you can.

Engine Compartment Fuse Block 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. The Engine Compartment Fuse Block is located in the engine compartment, on the driver side of the vehicle.

Lift the cover to access the fuse block. Notice: Spilling liquid on any electrical component on the vehicle may damage it. Always keep the covers on any electrical component. To remove fuses, hold the end of the fuse between your thumb and index finger and pull straight out.

GMC Sierra Owner Manual - 2011

Black plate (51,1)

Vehicle Care

10-51

Fuses

10

11

12

13

14

15

Usage Trailer Brake Controller Front Washer Oxygen Sensor Antilock Brakes System 2
Trailer Back-up Lamps Driver Side Low-Beam Headlamp Engine Control Module (Battery) Fuel Injectors, Ignition Coils (Right Side) Transmission Control Module (Battery) Vehicle Back-up Lamps

Fuses

Usage Right Trailer Stop/Turn Lamp Electronic Suspension Control, Automatic Level Control Exhaust

Fuses

Usage

Left Trailer Stop/Turn Lamp Engine Controls Engine Control Module, Throttle Control

GMC Sierra Owner Manual - 2011

Black plate (52,1)

10-52

Vehicle Care

Fuses

Usage

Fuses

Usage

Fuses

Usage

16

17

18

19

20

21

22
23

24

25

26

27

Passenger Side Low-Beam Headlamp Air Conditioning Compressor Oxygen Sensors Transmission Controls (Ignition) Fuel Pump Fuel System Control Module Not Used Not Used Fuel Injectors, Ignition Coils (Left Side) Trailer Park Lamps Driver Side Park Lamps Passenger Side Park Lamps

28
29

30

31

32

33

34

35

36

37

38

Fog Lamps Horn Passenger Side High-Beam Headlamp Daytime Running Lamps (DRL) Driver Side High-Beam Headlamp Daytime Running Lamps 2
Sunroof Key Ignition System, Theft Deterrent System Windshield Wiper SEO B2 Upfitter Usage (Battery) Electric Adjustable Pedals

39

40

41
42

43

44

45

46

47

48

49

50

Climate Controls (Battery) Airbag System (Ignition) Amplifier Audio System Miscellaneous (Ignition), Cruise Control Not Used Airbag System (Battery) Instrument Panel Cluster Power Take-Off Auxiliary Climate Control (Ignition) Center High-Mounted Stoplamp (CHMSL) Rear Defogger

GMC Sierra Owner Manual - 2011

Black plate (53,1)

Fuses

Usage

51

52

53

54

55

56

Heated Mirrors SEO B1 Upfitter Usage (Battery) Cigarette Lighter, Auxiliary Power Outlet SEO Upfitter Usage Climate Controls (Ignition) Engine Control Module, Secondary Fuel Pump (Ignition)

J-Case Fuses

57
58

59

Usage

Cooling Fan 1
Not Used Heavy Duty Antilock Brake System

J-Case Fuses

Usage

60

61

62

63

64

65

66

67

68

69

70

Cooling Fan 2
Antilock Brake System 1
Starter Stud 2
(Trailer Brakes) Left Bussed Electrical Center 1
Not Used Heated Windshield Washer System Transfer Case Stud 1 (Trailer Connector Battery Power) (Optional - 40A Fuse Required) Mid-Bussed Electrical Center 1
Climate Control Blower

Vehicle Care

10-53

J-Case Fuses

71

72

Usage

Not Used Left Bussed Electrical Center 2

Relays

Usage

FAN HI

FAN LO

FAN CNTRL

HDLP LO/HID FOG LAMP A/C CMPRSR STRTR PWR/TRN FUEL PMP PRK LAMP

Cooling Fan High Speed Cooling Fan Low Speed Cooling Fan Control Low-Beam Headlamp Front Fog Lamps Air Conditioning Compressor Starter Powertrain Fuel Pump Parking Lamps

GMC Sierra Owner Manual - 2011

Black plate (54,1)

10-54

Vehicle Care

Relays

REAR DEFOG RUN/CRNK

Usage

Rear Defogger

Switched Power

Instrument Panel Fuse Block

The instrument panel fuse block access door is located on the driver side edge of the instrument panel. Pull off the cover to access the fuse block.

The vehicle may not be equipped with all of the fuses, relays, and features shown.

Fuses

Usage

Rear Seats Rear Accessory Power Outlet

Fuses

Usage Steering Wheel Controls Backlight Driver Door Module Dome Lamps, Driver Side Turn Signal

GMC Sierra Owner Manual - 2011

Black plate (55,1)

Vehicle Care

10-55

Fuses

Usage

Fuses

Usage

Fuses

Usage

10

11

12

13
14

Driver Side Turn Signal, Stoplamp Instrument Panel Back Lighting Passenger Side Turn Signal, Stoplamp Passenger Door Module, Driver Unlock Power Door Lock 2
(Unlock Feature) Power Door Lock 2
(Lock Feature) Stoplamps, Center High‐ Mounted Stoplamp Rear Climate Controls Power Mirror

15

16

17

18

19

20

21

22

23
24

Body Control Module (BCM) Accessory Power Outlets Interior Lamps Power Door Lock 1
(Unlock Feature) Rear Seat Entertainment Ultrasonic Rear Parking Assist, Power Liftgate Power Door Lock 1
(Lock Feature) Driver Information Center (DIC) Rear Wiper Cooled Seats

25

26

Driver Seat Module, Remote Keyless Entry System Driver Power Door Lock (Unlock Feature)

Circuit Breaker

LT DR

Usage

Driver Side Power Window Circuit Breaker

Harness Connector

LT DR

BODY BODY

Usage

Driver Door Harness Connection Harness Connector Harness Connector

GMC Sierra Owner Manual - 2011

Black plate (56,1)

10-56

Vehicle Care

Center Instrument Panel Fuse Block The center instrument panel fuse block is located underneath the instrument panel, to the left of the steering column. Top View

Circuit Breaker

CB1

CB2

CB3

CB4

Usage

Passenger Side Power Window Circuit Breaker Passenger Seat Circuit Breaker Driver Seat Circuit Breaker Rear Sliding Window

Harness Connector

BODY 2

BODY 1

BODY 3

HEADLINER

HEADLINER

HEADLINER

SEO/

UPFITTER

Usage Body Harness Connector 2
Body Harness Connector 1
Body Harness Connector 3
Headliner Harness Connector 3
Headliner Harness Connector 2
Headliner Harness Connector 1
Special Equipment Option Upfitter Harness Connector

GMC Sierra Owner Manual - 2011

Black plate (57,1)

Wheels and Tires

Tires Your new vehicle comes with high-quality tires made by a leading tire manufacturer. If you ever have questions about your tire warranty and where to obtain service, see your vehicle Warranty booklet for details. For additional information refer to the tire manufacturer. { WARNING . Poorly maintained and

improperly used tires are dangerous.

. Overloading the tires can

cause overheating as a result of too much flexing. There could be a blowout and a serious crash. See Vehicle Load Limits on page 9‑25.

(Continued)

Vehicle Care

10-57

WARNING (Continued)

WARNING (Continued)

. Improperly repaired tires

can cause a crash. Only the dealer or an authorized tire service center should repair, replace, dismount, and mount the tires.

. Do not spin the tires in

excess of 55 km/h (35 mph) on slippery surfaces such as snow, mud, ice, etc. Excessive spinning may cause the tires to explode.

See Tire Pressure for High-Speed Operation on page 10‑67 for inflation pressure adjustment for high speed driving.

. Underinflated tires pose the same danger as overloaded tires. The resulting crash could cause serious injury. Check all tires frequently to maintain the recommended pressure. Tire pressure should be checked when the tires are cold.

. Overinflated tires are more likely to be cut, punctured, or broken by a sudden impact — such as when hitting a pothole. Keep tires at the recommended pressure. . Worn or old tires can cause a crash. If the tread is badly worn, replace them.

. Replace any tires that have been damaged by impacts with potholes, curbs, etc.

(Continued)

GMC Sierra Owner Manual - 2011

Black plate (58,1)

10-58

Vehicle Care

20‐Inch Tires If your vehicle has the optional 20‐inch P275/55R20 size tires, they are classified as touring tires and are designed for on road use. The low‐profile, wide tread design is not recommended for “off‐road” driving or commercial uses such as snow plowing. See Off-Road Driving on page 9‑7
and Adding a Snow Plow or Similar Equipment on page 9‑125 for additional information. Notice: If the vehicle has low‐profile tires, they are more susceptible to damage from road hazards or curb impact than standard profile tires.

Tire and/or wheel assembly damage can occur when coming into contact with road hazards like, potholes, or sharp edged objects, or when sliding into a curb. The vehicle warranty does not cover this type of damage. Keep tires set to the correct inflation pressure and, when possible avoid contact with curbs, potholes, and other road hazards.

Tire Sidewall Labeling Useful information about a tire is molded into the sidewall. The following illustrations are examples of a typical P‐Metric and a LT‐Metric tire sidewall.

Passenger (P‐Metric) Tire (A) Tire Size: The tire size code is a combination of letters and numbers used to define a particular tire's width, height, aspect ratio, construction type, and service description. See the “Tire Size” illustration later in this section for more detail.

GMC Sierra Owner Manual - 2011

Black plate (59,1)

Vehicle Care

10-59

(B) TPC Spec (Tire Performance Criteria Specification): Original equipment tires designed to GM's specific tire performance criteria have a TPC specification code molded onto the sidewall. GM's TPC specifications meet or exceed all federal safety guidelines. (C) DOT (Department of Transportation): The Department of Transportation (DOT) code indicates that the tire is in compliance with the U.S. Department of Transportation Motor Vehicle Safety Standards. (D) Tire Identification Number (TIN): The letters and numbers following DOT code are the Tire Identification Number (TIN). The TIN shows the manufacturer and plant code, tire size, and date the tire was manufactured.

The TIN is molded onto both sides of the tire, although only one side may have the date of manufacture. (E) Tire Ply Material: The type of cord and number of plies in the sidewall and under the tread. (F) Uniform Tire Quality Grading (UTQG): Tire manufacturers are required to grade tires based on three performance factors: treadwear, traction, and temperature resistance. For more information, see Uniform Tire Quality Grading on page 10‑80. (G) Maximum Cold Inflation Load Limit: Maximum load that can be carried and the maximum pressure needed to support that load. For information on recommended tire pressure see Tire Pressure on page 10‑66 and Vehicle Load Limits on page 9‑25.

Light Truck (LT-Metric) Tire

(A) Tire Size: The tire size code is a combination of letters and numbers used to define a particular tire's width, height, aspect ratio, construction type, and service description. See the “Tire Size” illustration later in this section for more detail.

GMC Sierra Owner Manual - 2011

Black plate (60,1)

10-60

Vehicle Care

(B) TPC Spec (Tire Performance Criteria Specification): Original equipment tires designed to GM's specific tire performance criteria have a TPC specification code molded onto the sidewall. GM's TPC specifications meet or exceed all federal safety guidelines. (C) Dual Tire Maximum Load: Maximum load that can be carried and the maximum pressure needed to support that load when used in a dual configuration. For information on recommended tire pressure see Tire Pressure on page 10‑66
and Vehicle Load Limits on page 9‑25.

(D) DOT (Department of Transportation): The Department of Transportation (DOT) code indicates that the tire is in compliance with the U.S. Department of Transportation Motor Vehicle Safety Standards. (E) Tire Identification Number (TIN): The letters and numbers following DOT code are the Tire Identification Number (TIN). The TIN shows the manufacturer and plant code, tire size, and date the tire was manufactured. The TIN is molded onto both sides of the tire, although only one side may have the date of manufacture.

(F) Tire Ply Material: The type of cord and number of plies in the sidewall and under the tread. (G) Single Tire Maximum Load: Maximum load that can be carried and the maximum pressure needed to support that load when used as a single. For information on recommended tire pressure see Tire Pressure on page 10‑66
and Vehicle Load Limits on page 9‑25.

GMC Sierra Owner Manual - 2011

Black plate (61,1)

(C) Aspect Ratio: A two‐digit number that indicates the tire height‐to‐width measurements. For example, if the tire size aspect ratio is 75, as shown in item C of the tire illustration, it would mean that the tire's sidewall is 75 percent as high as it is wide. (D) Construction Code: A letter code is used to indicate the type of ply construction in the tire. The letter R means radial ply construction; the letter D means diagonal or bias ply construction; and the letter B means belted‐bias ply construction. (E) Rim Diameter: Diameter of the wheel in inches.

Tire Designations

Tire Size The following examples show the different parts of a tire size.

Passenger (P‐Metric) Tire

(A) Passenger (P‐Metric) Tire: The United States version of a metric tire sizing system. The letter P as the first character in the tire size means a passenger vehicle tire engineered to standards set by the U.S. Tire and Rim Association. (B) Tire Width: The three‐digit number indicates the tire section width in millimeters from sidewall to sidewall.

Vehicle Care

10-61

(F) Service Description: These characters represent the load index and speed rating of the tire. The load index represents the load carrying capacity a tire is certified to carry. The speed rating is the maximum speed a tire is certified to carry a load.

Light Truck (LT‐Metric) Tire

(A) Light Truck (LT‐Metric) Tire: The United States version of a metric tire sizing system. The letters LT as the first two characters in the tire size means a light truck tire engineered to standards set by the U.S. Tire and Rim Association.

GMC Sierra Owner Manual - 2011

Black plate (62,1)

10-62

Vehicle Care

(B) Tire Width: The three‐digit number indicates the tire section width in millimeters from sidewall to sidewall. (C) Aspect Ratio: A two‐digit number that indicates the tire height‐to‐width measurements. For example, if the tire size aspect ratio is 75, as shown in item C of the light truck (LT‐Metric) tire illustration, it would mean that the tire's sidewall is 75 percent as high as it is wide. (D) Construction Code: A letter code is used to indicate the type of ply construction in the tire. The letter R means radial ply construction; the letter D means diagonal or bias ply construction; and the letter B means belted‐bias ply construction.

(E) Rim Diameter: Diameter of the wheel in inches. (F) Load Range : Load Range. (G) Service Description: The service description indicates the load index and speed rating of a tire. If two numbers are given as in the example, 120/116, then this represents the load index for single versus dual wheel usage (single/dual). The speed rating is the maximum speed a tire is certified to carry a load.

Tire Terminology and Definitions Air Pressure: The amount of air inside the tire pressing outward on each square inch of the tire. Air pressure is expressed in psi (pounds per square inch) or kPa (kilopascal).

Accessory Weight: This means the combined weight of optional accessories. Some examples of optional accessories are, automatic transmission, power steering, power brakes, power windows, power seats, and air conditioning. Aspect Ratio: The relationship of a tire's height to its width. Belt: A rubber coated layer of cords that is located between the plies and the tread. Cords may be made from steel or other reinforcing materials. Bead: The tire bead contains steel wires wrapped by steel cords that hold the tire onto the rim.

GMC Sierra Owner Manual - 2011

Black plate (63,1)

Bias Ply Tire: A pneumatic tire in which the plies are laid at alternate angles less than 90 degrees to the centerline of the tread. Cold Tire Pressure: The amount of air pressure in a tire, measured in kPa (kilopascal) or psi (pounds per square inch) before a tire has built up heat from driving. See Tire Pressure on page 10‑66. Curb Weight: The weight of a motor vehicle with standard and optional equipment including the maximum capacity of fuel, oil, and coolant, but without passengers and cargo.

DOT Markings: A code molded into the sidewall of a tire signifying that the tire is in compliance with the U.S. Department of Transportation (DOT) motor vehicle safety standards. The DOT code includes the Tire Identification Number (TIN), an alphanumeric designator which can also identify the tire manufacturer, production plant, brand, and date of production. GVWR: Gross Vehicle Weight Rating. See Vehicle Load Limits on page 9‑25. GAWR FRT: Gross Axle Weight Rating for the front axle. See Vehicle Load Limits on page 9‑25.

Vehicle Care

10-63

GAWR RR: Gross Axle Weight Rating for the rear axle. See Vehicle Load Limits on page 9‑25. Intended Outboard Sidewall: The side of an asymmetrical tire, that must always face outward when mounted on a vehicle. Kilopascal (kPa): The metric unit for air pressure. Light Truck (LT‐Metric) Tire: A tire used on light duty trucks and some multipurpose passenger vehicles. Load Index: An assigned number ranging from 1 to 279
that corresponds to the load carrying capacity of a tire.

GMC Sierra Owner Manual - 2011

Black plate (64,1)

10-64

Vehicle Care

Maximum Inflation Pressure: The maximum air pressure to which a cold tire can be inflated. The maximum air pressure is molded onto the sidewall. Maximum Load Rating: The load rating for a tire at the maximum permissible inflation pressure for that tire. Maximum Loaded Vehicle Weight: The sum of curb weight, accessory weight, vehicle capacity weight, and production options weight. Normal Occupant Weight: The number of occupants a vehicle is designed to seat multiplied by 68 kg (150 lbs). See Vehicle Load Limits on page 9‑25.

Occupant Distribution: Designated seating positions. Outward Facing Sidewall: The side of an asymmetrical tire that has a particular side that faces outward when mounted on a vehicle. The side of the tire that contains a whitewall, bears white lettering, or bears manufacturer, brand, and/or model name molding that is higher or deeper than the same moldings on the other sidewall of the tire. Passenger (P-Metric) Tire: A tire used on passenger cars and some light duty trucks and multipurpose vehicles.

Recommended Inflation Pressure: Vehicle manufacturer's recommended tire inflation pressure as shown on the tire placard. See Tire Pressure on page 10‑66 and Vehicle Load Limits on page 9‑25. Radial Ply Tire: A pneumatic tire in which the ply cords that extend to the beads are laid at 90 degrees to the centerline of the tread. Rim: A metal support for a tire and upon which the tire beads are seated. Sidewall: The portion of a tire between the tread and the bead.

GMC Sierra Owner Manual - 2011

Black plate (65,1)

Speed Rating: An alphanumeric code assigned to a tire indicating the maximum speed at which a tire can operate. Traction: The friction between the tire and the road surface. The amount of grip provided. Tread: The portion of a tire that comes into contact with the road. Treadwear Indicators: Narrow bands, sometimes called wear bars, that show across the tread of a tire when only 1.6 mm (1/16 in) of tread remains. See When It Is Time for New Tires on page 10‑76.

UTQGS (Uniform Tire Quality Grading Standards): A tire information system that provides consumers with ratings for a tire's traction, temperature, and treadwear. Ratings are determined by tire manufacturers using government testing procedures. The ratings are molded into the sidewall of the tire. See Uniform Tire Quality Grading on page 10‑80. Vehicle Capacity Weight: The number of designated seating positions multiplied by 68 kg (150 lbs) plus the rated cargo load. See Vehicle Load Limits on page 9‑25.

Vehicle Care

10-65

Vehicle Maximum Load on the Tire: Load on an individual tire due to curb weight, accessory weight, occupant weight, and cargo weight. Vehicle Placard: A label permanently attached to a vehicle showing the vehicle capacity weight and the original equipment tire size and recommended inflation pressure. See “Tire and Loading Information Label” under Vehicle Load Limits on page 9‑25.

GMC Sierra Owner Manual - 2011

Black plate (66,1)

10-66

Vehicle Care

Tire Pressure Tires need the correct amount of air pressure to operate effectively. Notice: Neither tire underinflation nor overinflation is good. Underinflated tires, or tires that do not have enough air, can result in:

. Tire overloading and

over-heating which could lead to a blowout.

. Premature or

irregular wear. . Poor handling. . Reduced fuel economy.

Overinflated tires, or tires that have too much air, can result in:

. Unusual wear. . Poor handling. . Rough ride. . Needless damage from

road hazards.

A vehicle-specific Tire and Loading Information label is attached to the vehicle. This label shows the vehicle's original equipment tires and the correct inflation pressures for the tires when they are cold. The recommended cold tire inflation pressure, shown on the label, is the minimum amount of air pressure needed to support the vehicle's maximum load-carrying capacity.

For additional information regarding how much weight the vehicle can carry, and an example of the Tire and Loading Information label, see Vehicle Load Limits on page 9‑25. How you load the vehicle affects vehicle handling and ride comfort. Never load the vehicle with more weight than it was designed to carry.

When to Check Check the tires once a month or more. Do not forget to check the pressure of the spare tire, if the vehicle has one. See Full-Size Spare Tire on page 10‑97 for additional information.

GMC Sierra Owner Manual - 2011

Black plate (67,1)

How to Check Use a good quality pocket-type gauge to check tire pressure. You cannot tell if the tires are properly inflated simply by looking at them. Radial tires may look properly inflated even when they are under-inflated. Check the tire's inflation pressure when the tires are cold. Cold means the vehicle has been sitting for at least three hours or driven no more than 1.6 km (1 mile). Remove the valve cap from the tire valve stem. Press the tire gauge firmly onto the valve to get a pressure measurement. If the cold tire inflation pressure matches the recommended pressure on the Tire and Loading Information label, no further adjustment is necessary. If the pressure is low, add air until you reach the recommended amount.

If you overfill the tire, release air by pushing on the metal stem in the center of the tire valve. Recheck the tire pressure with the tire gauge. Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture.

Tire Pressure for High-Speed Operation

{ WARNING

Driving at high speeds, 160 km/h (100 mph) or higher, puts an additional strain on tires. Sustained high-speed driving causes excessive heat build up and can cause sudden tire failure. You could have a crash and you or others could be killed. Some high-speed rated tires require

(Continued)

Vehicle Care

10-67

WARNING (Continued)

inflation pressure adjustment for high speed operation. When speed limits and road conditions are such that a vehicle can be driven at high speeds, make sure the tires are rated for high speed operation, in excellent condition, and set to the correct cold tire inflation pressure for the vehicle load.

Vehicles with P265/70R17 or P275/55R20 size tires require inflation pressure adjustment when driving the vehicle at speeds