2012 GMC Sierra Owners Manual

Messages on page 5‑42. Change the oil as soon as possible within the next 1 000 km (600 mi). It is possible that, if driving under the

best conditions, the oil life system might indicate that an oil change is not necessary for up to a year. The engine oil and filter must be changed at least once a year and, at this time, the system must be reset. For vehicles without the CHANGE ENGINE OIL SOON message, an oil change is needed when the OIL LIFE REMAINING percentage is near 0%. Your dealer has trained service people who will perform this work and reset the system. It is also important to check the oil regularly over the course of an oil drain interval and keep it at the proper level. If the system is ever reset accidentally, the oil must be changed at 5 000 km (3,000 mi) since the last oil change. Remember to reset the oil life system whenever the oil is changed.

How to Reset the Engine Oil Life System Reset the system whenever the engine oil is changed so that the system can calculate the next engine oil change. Always reset the engine oil life to 100% after every oil change. It will not reset itself. To reset the system on most vehicles: 1. Display the OIL LIFE

REMAINING on the DIC. If the vehicle does not have DIC buttons, the vehicle must be in P (Park) to access this display. See Driver Information Center (DIC) on page 5‑30.

2. Press and hold the SET/RESET

button on the DIC, or the trip odometer reset stem if the vehicle does not have DIC buttons, for more than five seconds. The oil life will change to 100%.

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On all vehicles, the Engine Oil Life System can be reset as follows: 1. Turn the ignition to ON/RUN with

the engine off.

2. Fully press the accelerator pedal

slowly three times within five seconds.

3. Display the OIL LIFE

REMAINING on the DIC. If the display shows 100%, the system is reset. See Driver Information Center (DIC) on page 5‑30.

If the vehicle has a CHANGE ENGINE OIL SOON message and it comes back on when the vehicle is started and/or the OIL LIFE REMAINING is near 0%, the engine oil life system has not been reset. Repeat the procedure.

Automatic Transmission Fluid (4-Speed Transmission)

When to Check and Change Automatic Transmission Fluid A good time to check the automatic transmission fluid level is when the engine oil is changed. Change the fluid and filter at the intervals listed in Maintenance Schedule on page 11‑3 and be sure to use the transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12. How to Check Automatic Transmission Fluid Because this operation can be a little difficult, it may be best to have this done at the dealer service department. If not taken to the dealer, be sure to follow all the instructions here or a false reading on the dipstick could result.

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Notice: Too much or too little fluid can damage the transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too little fluid could cause the transmission to overheat. Be sure to get an accurate reading if checking the transmission fluid. Wait at least 30 minutes before checking the transmission fluid level if you have been driving: . When outside temperatures are

above 32°C (90°F).

. At high speed for quite a while. In heavy traffic — especially in hot weather.

. While pulling a trailer. To get the right reading, the fluid should be at normal operating temperature, which is 82°C to 93°C (180°F to 200°F).

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Vehicle Care

Get the vehicle warmed up by driving about 24 km (15 miles) when outside temperatures are above 10°C (50°F). If it is colder than 10°C (50°F), drive the vehicle in 3 (Third) until the engine temperature gauge moves and then remains steady for 10 minutes. A cold fluid check can be made after the vehicle has been sitting for eight hours or more with the engine off, but this is used only as a reference. Let the engine run at idle for five minutes if outside temperatures are 10°C (50°F) or more. If it is colder than 10°C (50°F), the engine may have to idle longer. Should the fluid level be low during this cold check, the fluid must be checked when hot before adding fluid. Checking the fluid hot will give you a more accurate reading of the fluid level.

Checking the Fluid Level Prepare the vehicle as follows: 1. Park the vehicle on a level

place. Keep the engine running. 2. With the parking brake applied, place the shift lever in P (Park).

3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about three seconds in each range. Then, position the shift lever in P (Park).

4. Let the engine run at idle for

three minutes or more.

Then, without shutting off the engine, follow these steps:

1. Locate the transmission dipstick handle with this graphic which is located at the rear of the engine compartment, on the passenger side of the vehicle. See Engine Compartment Overview on page 10‑6 for more information on location.

2. Flip the handle up, then pull out

the dipstick and wipe it with a clean rag or paper towel.

3. Push it back in all the way, wait

three seconds and then pull it back out again.

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4. Check both sides of the dipstick,

and read the lower level. The fluid level must be in the COLD area, below the cross-hatched area, for a cold check or in the HOT or cross-hatched area for a hot check. Be sure to keep the dipstick pointed down to get an accurate reading. If the fluid level is in the acceptable range, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place.

5.

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Notice: Use of the incorrect automatic transmission fluid may damage the vehicle, and the damages may not be covered by the vehicle warranty. Always use the automatic transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12. . After adding fluid, recheck the fluid level as described under “How to Check Automatic Transmission Fluid,” earlier in this section.

. When the correct fluid level is

obtained, push the dipstick back in all the way; then flip the handle down to lock the dipstick in place.

Consistency of Readings Always check the fluid level at least twice using the procedure described previously. Consistency (repeatable readings) is important to maintaining proper fluid level. If readings are still inconsistent, contact the dealer. How to Add Automatic Transmission Fluid Refer to Recommended Fluids and Lubricants on page 11‑12 to determine what kind of transmission fluid to use. Using a funnel, add fluid down the transmission dipstick tube only after checking the transmission fluid while it is hot. A cold check is used only as a reference. If the fluid level is low, add only enough of the proper fluid to bring the level up to the HOT area for a hot check. It does not take much fluid, generally less than 0.5 Liter (1 Pint). Do not overfill.

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Automatic Transmission Fluid (6-Speed Transmission)

When to Check and Change Automatic Transmission Fluid It is usually not necessary to check the transmission fluid level. The only reason for fluid loss is a transmission leak or overheated transmission. If a small leak is suspected, then use the following checking procedures to check the fluid level. However, if there is a large leak, then it may be necessary to have the vehicle towed to a dealer service department and have it repaired before driving the vehicle further. Notice: Use of the incorrect automatic transmission fluid may damage the vehicle, and the damages may not be covered by the vehicle warranty. Always use the automatic transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12.

Change the fluid and filter at the scheduled maintenance intervals listed in Maintenance Schedule on page 11‑3. Be sure to use the transmission fluid listed in Recommended Fluids and Lubricants on page 11‑12. How to Check Automatic Transmission Fluid Notice: Too much or too little fluid can damage the transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too little fluid could cause the transmission to overheat. Be sure to get an accurate reading if checking the transmission fluid.

Before checking the fluid level, prepare the vehicle as follows: 1. Start the engine and park the

vehicle on a level surface. Keep the engine running.

2. Apply the parking brake and

place the shift lever in P (Park).

3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about three seconds in each range. Then, move the shift lever back to P (Park).

4. Allow the engine to idle

(500 – 800 rpm) for at least 1 minute. Slowly release the brake pedal.

5. Keep the engine running and press the Trip/Fuel button or trip odometer reset stem until TRANS TEMP (Transmission Temperature) displays on the Driver Information Center (DIC).

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6. Using the TRANS TEMP

reading, determine and perform the appropriate check procedure. If the TRANS TEMP reading is not within the required temperature ranges, allow the vehicle to cool, or operate the vehicle until the appropriate transmission fluid temperature is reached.

Cold Check Procedure Use this procedure only as a reference to determine if the transmission has enough fluid to be operated safely until a hot check procedure can be made. The hot check procedure is the most accurate method to check the fluid level. Perform the hot check procedure at the first opportunity. Use this cold check procedure to check fluid level when the transmission temperature is between 27°C and 32°C (80°F and 90°F).

1. Locate the transmission

dipstick at the rear of the engine compartment, on the passenger side of the vehicle. See Engine Compartment Overview on page 10‑6 for more information.

2. Flip the handle up, then pull out

3.

the dipstick and wipe it with a clean rag or paper towel. Install the dipstick by pushing it back in all the way; wait three seconds, and then pull it back out again.

4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the reading.

5.

If the fluid level is below the COLD check band, add only enough fluid as necessary to bring the level into the COLD band. It does not take much fluid, generally less than 0.5 Liter (1 Pint). Do not overfill. 6. Perform a hot check at

7.

the first opportunity after the transmission reaches a normal operating temperature between 71°C to 93°C (160°F to 200°F). If the fluid level is in the acceptable range, push the dipstick back in all the way, then flip the handle down to lock the dipstick in place.

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Hot Check Procedure Use this procedure to check the transmission fluid level when the transmission fluid temperature is between 71°C and 93°C (160°F and 200°F). The hot check is the most accurate method to check the fluid level. The hot check should be performed at the first opportunity in order to verify the cold check. The fluid level rises as fluid temperature increases, so it is important to ensure the transmission temperature is within range.

See Engine Compartment Overview on page 10‑6 for more information.

2. Flip the handle up, then pull out

3.

the dipstick and wipe it with a clean rag or paper towel. Install the dipstick by pushing it back in all the way; wait three seconds, and then pull it back out again.

4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the reading.

6.

within the HOT band, and the transmission temperature is between 71°C and 93°C (160°F and 200°F), add or drain fluid as necessary to bring the level into the HOT band. If the fluid level is low, add only enough fluid to bring the level into the HOT band. It does not take much fluid, generally less than 0.5 L (1 pint). Do not overfill. If the fluid level is in the acceptable range, push the dipstick back in all the way, then flip the handle down to lock the dipstick in place.

1. Locate the transmission dipstick

5. Safe operating level is within the

at the rear of the engine compartment, on the passenger side of the vehicle.

HOT cross hatch band on the dipstick. If the fluid level is not

Consistency of Readings Always check the fluid level at least twice using the procedure described previously. Consistency (repeatable readings) is important to maintaining proper fluid level. If readings are still inconsistent, contact the dealer.

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How to Inspect the Engine Air Cleaner/Filter To inspect the air cleaner/filter, remove the engine air cleaner/filter from the vehicle by following Steps 1 through 6. When the engine air cleaner/filter is removed, lightly shake it to release loose dust and dirt. If the engine air cleaner/ filter remains covered with dirt, a new filter is required. Never use compressed air to clean the filter.

Engine Air Cleaner/Filter If the vehicle has a diesel engine, see “Pickup Models” under “Engine Air Cleaner/Filter” in the Duramax® Diesel Supplement for the correct inspection and replacement procedures. See Engine Compartment Overview on page 10‑6 for the location of the engine air cleaner/filter. When to Inspect the Engine Air Cleaner/Filter Inspect the air cleaner/filter at the scheduled maintenance intervals and replace it at the first oil change after each 80 000 km (50,000 mi) interval. See Maintenance Schedule on page 11‑3 for more information. If driving on dusty/dirty conditions, inspect the filter at each engine oil change.

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Replacing the Engine Air Cleaner/ Filter

1. Locate the air cleaner/filter

assembly. See Engine Compartment Overview on page 10‑6.

2. Loosen the four screws on the cover of the housing and lift up the cover.

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Vehicle Care

3. Remove the engine air cleaner/

filter from the housing. Take care to dislodge as little dirt as possible.

4. Clean the engine air cleaner/ filter sealing surfaces and the housing. Inspect or replace the engine air cleaner/filter.

5.

6. Reinstall the cover and tighten

the screws.

{ WARNING

Operating the engine with the air cleaner/filter off can cause you or others to be burned. The air cleaner not only cleans the air; it helps to stop flames if the engine backfires. Use caution when working on the engine and do not drive with the air cleaner/filter off.

Cooling System If the vehicle has the Duramax® Diesel engine, see the Duramax® Diesel Supplement for more information. The cooling system allows the engine to maintain the correct working temperature.

5.3 L Engine Shown (4.3 L, 4.8 L, 6.0 L and, 6.2 L Engines Similar)

A. Coolant Surge Tank B. Coolant Surge Tank

Pressure Cap

C. Engine Cooling Fan

(Out of View)

{ WARNING

An electric engine cooling fan can start even when the engine is not running. To avoid injury, always keep hands, clothing, and tools away from any engine cooling fan.

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{ WARNING

Heater and radiator hoses, and other engine parts, can be very hot. Do not touch them. If you do, you can be burned. Do not run the engine if there is a leak. If you run the engine, it could lose all coolant. That could cause an engine fire, and you could be burned. Get any leak fixed before you drive the vehicle.

Notice: Using coolant other than DEX-COOL® can cause premature engine, heater core, or radiator corrosion. In addition, the engine coolant could require changing sooner, at 50 000 km (30,000 mi) or 24 months, whichever occurs first. Any repairs would not be covered by the vehicle warranty. Always use DEX-COOL (silicate-free) coolant in the vehicle.

Engine Coolant The cooling system in the vehicle is filled with DEX-COOL® engine coolant. This coolant is designed to remain in the vehicle for 5 years or 240 000 km (150,000 mi), whichever occurs first. The following explains the cooling system and how to check and add coolant when it is low. If there is a problem with engine overheating, see Engine Overheating on page 10‑22. What to Use

{ WARNING

Adding only plain water or some other liquid to the cooling system can be dangerous. Plain water and other liquids, can boil before the proper coolant mixture will. The coolant warning system is set for the proper coolant mixture. With plain water or the wrong

(Continued)

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WARNING (Continued)

mixture, the engine could get too hot but you would not get the overheat warning. The engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOL coolant.

Use a 50/50 mixture of clean, drinkable water and DEX-COOL coolant. If using this mixture, nothing else needs to be added. This mixture: . Gives freezing protection down

to −37°C (−34°F), outside temperature

. Gives boiling protection up to

129°C (265°F), engine temperature

. Protects against rust and

corrosion

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Vehicle Care

. Will not damage aluminum parts . Helps keep the proper engine

temperature

Notice: If an improper coolant mixture is used, the engine could overheat and be badly damaged. The repair cost would not be covered by the vehicle warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core, and other parts. Notice: If extra inhibitors and/or additives are used in the vehicle cooling system, the vehicle could be damaged. Use only the proper mixture of the engine coolant listed in this manual for the cooling system. See Recommended Fluids and Lubricants on page 11‑12 for more information.

Never dispose of engine coolant by putting it in the trash, pouring it on the ground, or into sewers, streams, or bodies of water. Have the coolant changed by an authorized service center, familiar with legal requirements regarding used coolant disposal. This will help protect the environment and your health. Checking Coolant The coolant surge tank is located in the engine compartment on the passenger side of the vehicle. See Engine Compartment Overview on page 10‑6 for more information on location. The vehicle must be on a level surface when checking the coolant level. Check to see if coolant is visible in the coolant surge tank. If the coolant inside the coolant surge tank is boiling, do not do anything else until

it cools down. If coolant is visible but the coolant level is not at or above the FULL COLD mark, add a 50/50 mixture of clean, drinkable water and DEX-COOL coolant at the coolant surge tank, but be sure the cooling system is cool before this is done.

The coolant level should be at or above the FULL COLD mark. If it is not, there may be a leak in the cooling system.

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How to Add Coolant to the Coolant Surge Tank for Gasoline Engines If the vehicle has a diesel engine, see “Cooling System” in the Duramax Diesel Supplement for the proper coolant fill procedure.

{ WARNING

You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts are hot enough. Do not spill coolant on a hot engine.

Notice: This vehicle has a specific coolant fill procedure. Failure to follow this procedure could cause the engine to overheat and be severely damaged.

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{ WARNING

If no coolant is visible in the surge tank, add coolant as follows:

An electric engine cooling fan under the hood can start up even when the engine is not running and can cause injury. Keep hands, clothing, and tools away from any underhood electric fan.

{ WARNING

Steam and scalding liquids from a hot cooling system can blow out and burn you badly. They are under pressure, and if you turn the coolant surge tank pressure cap — even a little — they can come out at high speed. Never turn the cap when the cooling system, including the coolant surge tank pressure cap, is hot. Wait for the cooling system and coolant surge tank pressure cap to cool if you ever have to turn the pressure cap.

1. Remove the coolant surge tank pressure cap when the cooling system, including the coolant surge tank pressure cap and upper radiator hose, is no longer hot. Turn the pressure cap slowly counterclockwise about one full turn. If a hiss is heard, wait for that to stop. A hiss means there is still some pressure left.

2. Keep turning the pressure cap

slowly, and remove it.

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Vehicle Care

mixture to the coolant surge tank until the level reaches the FULL COLD mark.

5. Replace the pressure cap. Be

sure the pressure cap is hand-tight and fully seated. 6. Verify coolant level after the

engine is shut off and the coolant is cold. If necessary, repeat coolant fill procedure Steps 1 through 6.

Notice: If the pressure cap is not tightly installed, coolant loss and possible engine damage may occur. Be sure the cap is properly and tightly secured.

Engine Overheating If the vehicle has the Duramax® Diesel engine, see the Duramax Diesel Supplement for more information. The vehicle has several indicators to warn of engine overheating.

There is a coolant temperature gauge on the vehicle's instrument panel. See Engine Coolant Temperature Gauge on page 5‑16. In addition, there are ENGINE OVERHEATED STOP ENGINE, ENGINE OVERHEATED IDLE ENGINE, and ENGINE POWER IS REDUCED messages in the Driver Information Center (DIC) on the instrument panel. See Engine Cooling System Messages on page 5‑41 and Engine Power Messages on page 5‑42. If the decision is made not to lift the hood when this warning appears, get service help right away. See Roadside Assistance Program (U.S. and Canada) on page 13‑7 or Roadside Assistance Program (Mexico) on page 13‑9. If the decision is made to lift the hood, make sure the vehicle is parked on a level surface.

3. Fill the coolant surge tank with the proper mixture to the FULL COLD mark.

4. With the coolant surge tank

pressure cap off, start the engine and let it run until the engine coolant temperature gauge indicates approximately 90°C (195°F). By this time, the coolant level inside the coolant surge tank may be lower. If the level is lower, add more of the proper

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Then check to see if the engine cooling fans are running. If the engine is overheating, both fans should be running. If they are not, do not continue to run the engine and have the vehicle serviced. Notice: Engine damage from running your engine without coolant is not covered by the vehicle warranty. See Overheated Engine Protection Operating Mode for information on driving to a safe place in an emergency. Notice: If the engine catches fire while driving with no coolant, the vehicle can be badly damaged. The costly repairs would not be covered by the vehicle warranty. See Overheated Engine Protection Operating Mode on page 10‑24 for information on driving to a safe place in an emergency.

If Steam is Coming from the Engine Compartment { WARNING

Steam from an overheated engine can burn you badly, even if you just open the hood. Stay away from the engine if you see or hear steam coming from it. Turn it off and get everyone away from the vehicle until it cools down. Wait until there is no sign of steam or coolant before you open the hood. If you keep driving when the vehicles engine is overheated, the liquids in it can catch fire. You or others could be badly burned. Stop the engine if it overheats, and get out of the vehicle until the engine is cool.

(Continued)

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WARNING (Continued)

See Overheated Engine Protection Operating Mode on page 10‑24 for information on driving to a safe place in an emergency.

If No Steam is Coming from the Engine Compartment The ENGINE OVERHEATED STOP ENGINE or the ENGINE OVERHEATED IDLE ENGINE message, along with a low coolant condition, can indicate a serious problem. If there is an engine overheat warning, but no steam is seen or heard, the problem may not be too serious. Sometimes the engine can get a little too hot when the vehicle: . Climbs a long hill on a hot day . Stops after high-speed driving

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Vehicle Care

Idles for long periods in traffic Tows a trailer; see Trailer Towing on page 9‑78.

If the ENGINE OVERHEATED STOP ENGINE or the ENGINE OVERHEATED IDLE ENGINE message appears with no sign of steam, try this for a minute or so: 1. Turn the air conditioning off. 2. Turn the heater on to the highest

3.

temperature and to the highest fan speed. Open the windows as necessary. If stopped in a traffic jam, apply the brake, shift to N (Neutral); otherwise, shift to the highest gear while driving — D (Drive) or 3 (Third).

If the temperature overheat gauge is no longer in the overheat zone or an overheat warning no longer displays, the vehicle can be driven. Continue to drive the vehicle slowly for about 10 minutes. Keep a safe

vehicle distance from the vehicle in front. If the warning does not come back on, continue to drive normally. If the warning continues, pull over, stop, and park the vehicle right away. If there is no sign of steam, idle the engine for five minutes while parked. If the warning is still displayed, turn off the engine until it cools down. Also, see “Overheated Engine Protection Operating Mode” later in this section.

Overheated Engine Protection Operating Mode If an overheated engine condition exists and the ENGINE POWER IS REDUCED message displays, an overheat protection mode which alternates firing groups of cylinders helps to prevent engine damage. In this mode, a loss in power and engine performance will be noticed.

This operating mode allows the vehicle to be driven to a safe place in an emergency. Driving extended km (mi) and/or towing a trailer in the overheat protection mode should be avoided. Notice: After driving in the overheated engine protection operating mode, to avoid engine damage, allow the engine to cool before attempting any repair. The engine oil will be severely degraded. Repair the cause of coolant loss, change the oil and reset the oil life system. See Engine Oil on page 10‑7.

Engine Fan If the vehicle has a clutched engine cooling fan, when the clutch is engaged, the fan spins faster to provide more air to cool the engine. In most everyday driving conditions, the fan is spinning slower and the clutch is not fully engaged. This improves fuel economy and reduces fan noise. Under heavy vehicle

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loading, trailer towing, and/or high outside temperatures, the fan speed increases as the clutch more fully engages, so an increase in fan noise may be heard. This is normal and should not be mistaken as the transmission slipping or making extra shifts. It is merely the cooling system functioning properly. The fan will slow down when additional cooling is not required and the clutch disengages. This fan noise may also be heard when starting the engine. It will go away as the fan clutch partially disengages. If the vehicle has electric cooling fans, the fans may be heard spinning at low speed during most everyday driving. The fans may turn off if no cooling is required. Under heavy vehicle loading, trailer towing, high outside temperatures, or operation of the air conditioning system, the fans may change to high speed and an increase in fan noise may be heard. This is normal and indicates that the cooling

system is functioning properly. The fans will change to low speed when additional cooling is no longer required.

Power Steering Fluid

See Engine Compartment Overview on page 10‑6 for reservoir location. When to Check Power Steering Fluid It is not necessary to regularly check power steering fluid unless there is a leak suspected in the system or an unusual noise is heard. A fluid loss in this system could indicate a problem. Have the system inspected and repaired.

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How to Check Power Steering Fluid Notice: Extremely small amounts of contamination can cause steering system damage and cause it to not work properly. Do not allow contaminants to contact the fluid side of the reservoir cap/ dipstick or to enter the reservoir. To check the power steering fluid: 1. Turn the key off and let the

engine compartment cool down. 2. Wipe the cap and the top of the

reservoir clean.

3. Unscrew the cap and wipe the

dipstick with a clean rag.

4. Replace the cap and completely

tighten it.

5. Remove the cap again and look at the fluid level on the dipstick.

The level should be at the FULL COLD mark. If necessary, add only enough fluid to bring the level up to the mark.

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Vehicle Care

What to Use To determine what kind of fluid to use, see Recommended Fluids and Lubricants on page 11‑12. Always use the proper fluid. Notice: Use of the incorrect fluid may damage the vehicle and the damages may not be covered by the vehicle's warranty. Always use the correct fluid listed in Recommended Fluids and Lubricants on page 11‑12.

Washer Fluid

What to Use When windshield washer fluid needs to be added, be sure to read the manufacturer's instructions before use. Use a fluid that has sufficient protection against freezing in an area where the temperature may fall below freezing.

Adding Washer Fluid The vehicle has a low washer fluid message on the DIC that comes on when the washer fluid is low. The message is displayed for 15 seconds at the start of each ignition cycle. When the WASHER FLUID LOW ADD FLUID message displays, washer fluid will need to be added to the windshield washer fluid reservoir.

Open the cap with the washer symbol on it. Add washer fluid until the tank is full. See Engine Compartment Overview on page 10‑6 for reservoir location.

Notice

. When using concentrated

washer fluid, follow the manufacturer's instructions for adding water.

. Do not mix water with

ready-to-use washer fluid. Water can cause the solution to freeze and damage the washer fluid tank and other parts of the washer system.

. Fill the washer fluid tank only

three-quarters full when it is very cold. This allows for fluid expansion if freezing occurs, which could damage the tank if it is completely full.

. Do not use engine coolant

(antifreeze) in the windshield washer. It can damage the windshield washer system and paint.

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Brakes This vehicle has front disc brakes and could have rear drum brakes or rear disc brakes. Disc brake pads have built-in wear indicators that make a high-pitched warning sound when the brake pads are worn and new pads are needed. The sound can come and go or be heard all the time the vehicle is moving, except when applying the brake pedal firmly.

{ WARNING

The brake wear warning sound means that soon the brakes will not work well. That could lead to a crash. When the brake wear warning sound is heard, have the vehicle serviced.

Notice: Continuing to drive with worn-out brake pads could result in costly brake repair.

Some driving conditions or climates can cause a brake squeal when the brakes are first applied or lightly applied. This does not mean something is wrong with the brakes. Properly torqued wheel nuts are necessary to help prevent brake pulsation. When tires are rotated, inspect brake pads for wear and evenly tighten wheel nuts in the proper sequence to torque specifications in Capacities and Specifications on page 12‑2. If the vehicle has rear drum brakes, they do not have wear indicators, but if a rear brake rubbing noise is heard, have the rear brake linings inspected immediately. Rear brake drums should be removed and inspected each time the tires are removed for rotation or changing. Drum brakes have an inspection hole to inspect lining wear during scheduled maintenance. When the front brake pads are replaced, have the rear brakes inspected, too.

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10-27

Brake linings should always be replaced as complete axle sets. Brake Pedal Travel See your dealer if the brake pedal does not return to normal height, or if there is a rapid increase in pedal travel. This could be a sign that brake service might be required. Brake Adjustment Every time the brakes are applied, with or without the vehicle moving, the brakes adjust for wear. Replacing Brake System Parts The braking system on a vehicle is complex. Its many parts have to be of top quality and work well together if the vehicle is to have really good braking. The vehicle was designed and tested with top-quality brake parts. When parts of the braking system are replaced, be sure to get new, approved replacement parts.

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Vehicle Care

If this is not done, the brakes might not work properly. For example, installing disc brake pads that are wrong for the vehicle, can change the balance between the front and rear brakes — for the worse. The braking performance expected can change in many other ways if the wrong replacement brake parts are installed.

Brake Fluid

The brake master cylinder reservoir is filled with DOT 3 brake fluid. See Engine Compartment Overview on page 10‑6 for the location of the reservoir.

There are only two reasons why the brake fluid level in the reservoir might go down:

The brake fluid level goes down because of normal brake lining wear. When new linings are installed, the fluid level goes back up.

. A fluid leak in the brake

hydraulic system can also cause a low fluid level. Have the brake hydraulic system fixed, since a leak means that sooner or later the brakes will not work well.

Do not top off the brake fluid. Adding fluid does not correct a leak. If fluid is added when the linings are worn, there will be too much fluid when new brake linings are installed. Add or remove brake fluid, as necessary, only when work is done on the brake hydraulic system.

{ WARNING

If too much brake fluid is added, it can spill on the engine and burn, if the engine is hot enough. You or others could be burned, and the vehicle could be damaged. Add brake fluid only when work is done on the brake hydraulic system. See “Checking Brake Fluid” in this section.

When the brake fluid falls to a low level, the brake warning light comes on. See Brake System Warning Light on page 5‑25. Refer to the Maintenance Schedule to determine when to check the brake fluid. See Maintenance Schedule on page 11‑3.

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Checking Brake Fluid Check brake fluid by looking at the brake fluid reservoir. See Engine Compartment Overview on page 10‑6.

The fluid level should be above MIN. If it is not, have the brake hydraulic system checked to see if there is a leak.

Vehicle Care

10-29

Notice

. Using the wrong fluid

can badly damage brake hydraulic system parts. For example, just a few drops of mineral-based oil, such as engine oil, in the brake hydraulic system can damage brake hydraulic system parts so badly that they will have to be replaced. Do not let someone put in the wrong kind of fluid.

. If brake fluid is spilled on the

vehicle's painted surfaces, the paint finish can be damaged. Be careful not to spill brake fluid on the vehicle. If you do, wash it off immediately.

After work is done on the brake hydraulic system, make sure the level is above the MIN but not over the MAX mark.

What to Add Use only new DOT 3 brake fluid from a sealed container. See Recommended Fluids and Lubricants on page 11‑12. Always clean the brake fluid reservoir cap and the area around the cap before removing it. This helps keep dirt from entering the reservoir.

{ WARNING

With the wrong kind of fluid in the brake hydraulic system, the brakes might not work well. This could cause a crash. Always use the proper brake fluid.

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10-30

Vehicle Care

Battery If the vehicle is a Hybrid, see the Hybrid Supplement for more information. This vehicle has a maintenance free battery (or batteries). Refer to the replacement number on the original battery label when a new battery is needed. See Engine Compartment Overview on page 10‑6 for battery location.

{ WARNING

Battery posts, terminals, and related accessories contain lead and lead compounds, chemicals known to the State of California to cause cancer and reproductive harm. Wash hands after handling.

Vehicle Storage

{ WARNING

Batteries have acid that can burn you and gas that can explode. You can be badly hurt if you are not careful. See Jump Starting on page 10‑88 for tips on working around a battery without getting hurt.

Infrequent Usage: Remove the black, negative (−) cable from the battery to keep the battery from running down. Extended Storage: Remove the black, negative (−) cable from the battery or use a battery trickle charger.

Four-Wheel Drive

Transfer Case

When to Check Lubricant Refer to Maintenance Schedule on page 11‑3 to determine when to check the lubricant.

How to Check Lubricant

Electric Shift Transfer Case

A. Fill Plug B. Drain Plug

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Vehicle Care

10-31

When to Change Lubricant Refer to Maintenance Schedule on page 11‑3 to determine how often to change the lubricant.

What to Use Refer to Recommended Fluids and Lubricants on page 11‑12 to determine what kind of lubricant to use.

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.

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. 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.

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10-32

Vehicle Care

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

1500 Series

A. Fill Plug B. Drain Plug

What to Use Refer to Recommended Fluids and Lubricants on page 11‑12 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.

All Except 1500 Series

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.

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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

Vehicle Care

10-33

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. 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.

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10-34

Vehicle Care

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 11‑12 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 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. 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.

Exhaust: . Removal of the muffler and/or

resonator.

. Removal of the exhaust pipes

and exhaust pipe clamps.

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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.

2. Firmly apply both the parking brake and the regular brake. See Parking Brake on page 9‑54. 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.

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 9‑54. Be ready to apply the regular brake immediately if the vehicle begins to move.

Vehicle Care

10-35

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.

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10-36

Vehicle Care

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.

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 Maintenance Schedule on page 11‑3 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.

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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.

Vehicle Care

10-37

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.

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 11‑15.

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

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10-38

Vehicle Care

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.

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.

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.

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.

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Bulb Replacement For the proper type of replacement bulbs, see Replacement Bulbs on page 10‑43. 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.

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.

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.

Vehicle Care

10-39

Headlamps, Front Turn Signal, Sidemarker, and Parking Lamps

A. Side Marker Lamp B. Low-Beam Headlamp C. High-Beam Headlamp D. Park/Turn Signal Lamp 1. Open the hood. See Hood on

page 10‑5

2. When replacing a driver side

bulb on a vehicle with duel batteries, see your dealer.

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10-40

Vehicle Care

3. When replacing a bulb on the

passenger side, remove the Engine Air Cleaner cover. See Engine Air Cleaner/Filter on page 10‑17 for more information.

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

5. Turn the bulb socket

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

6. Unplug the electrical connector

from the old bulb by releasing the clips on the bulb socket. 7. Replace it with a new bulb. 8. Plug in the electrical connector. 9. Reinstall the new bulb socket

into the headlamp assembly and turn it clockwise to secure.

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.

Taillamps (Chassis Cab Models)

A. Backup Lamp B. Stoplamp/Taillamp/Turn

Signal Lamp

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.

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To replace one of these bulbs: 1. Open the tailgate. See Tailgate

on page 2‑10 for more information.

4.

Install a new bulb into the socket, turn it clockwise, and press it in until it is tight.

5. Reinstall the lens and the four

screws.

Taillamps, Turn Signal, Stoplamps, and Back-Up Lamps

Vehicle Care

10-41

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.

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.

A. Stoplamp/Taillamp/Turn

Signal Lamp

B. Back-up Lamp

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Vehicle Care

Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp

A. Cargo Lamp B. Center High-Mounted Stoplamp

(CHMSL) Bulb

To replace one of these bulbs:

1. Remove the two screws and lift

off the lamp assembly.

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 assembly by turning it one quarter turn clockwise.

6. Reinstall the lamp assembly and

tighten the screws.

License Plate Lamp

A. License Plate Lamp Housing B. Bulb C. Bulb Socket To replace one of these bulbs: 1. Using a small flat-bladed tool,

insert the blade end at the back edge of the rear license plate lamp housing (A).

2. Gently push forward while lifting

the back edge of the lamp housing from the bumper opening.

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3. Turn the bulb socket (C)

one‐quarter turn to release the bulb socket from the lamp housing (A).

4. Pull the bulb (B) from the bulb

socket (C).

5. Reverse the steps to install.

Replacement Bulbs

Exterior Lamp

Back-up Lamp Back-up Lamp* Cargo Lamp