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When to Change Lubricant
Refer to the Maintenance Schedule to determine how
often to change the lubricant. SeeScheduled
Maintenance on page 6-5.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. SeePart C: Recommended
Fluids and Lubricants on page 6-31.
Front Axle
When to Check Lubricant
It is not necessary to regularly check front axle fluid
unless you suspect there is a leak or you hear an
unusual noise. A fluid loss could indicate a problem.
Have it inspected and repaired.
Notice:If you drive your vehicle through deep water
that is higher than the front or rear axle, water may
enter the axle housing and cause the axle lubricant to
break down. This could damage the gears inside.
Avoid driving your vehicle through deep water.
You should avoid driving your vehicle through deep
puddles or standing water. If you must drive through
water that is higher than the front or rear axle, see your
dealer immediately afterward to have the condition of
the axle lubricant checked.
How to Check Lubricant
To get an accurate reading, the vehicle should be on a
level surface.
If the level is below the bottom of the filler plug hole,
you may need to add some lubricant.
Add enough lubricant to raise the level to the bottom of
the filler plug hole.
What to Use
To determine what kind of lubricant to use seePart C:
Recommended Fluids and Lubricants on page 6-31.
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Wheel Loading
Wheels are stamped with a maximum load and cold
inflation rating. Be sure you do not exceed these limits.
Dual Tire Operation
When the vehicle is new, check the wheel nut tightness
on all wheels with a torque wrench after your first
100 miles (160 km) and then 1,000 miles (1 600 km) after
that. Whenever a wheel, wheel bolt or wheel nut is
removed or serviced, repeat the 100 miles (160 km), and
then 1,000 mile (1 600 km) wheel nut tightness check.
SeeTightening the Wheel Nuts on page 5-80for wheel
nut tightening information and proper torque values.
{CAUTION:
If you operate your vehicle with a tire that is badly
underinflated, the tire can overheat. An overheated
tire can lose air suddenly or catch fire. You or
others could be injured. Be sure all tires (including
the spare, if any) are properly inflated.
SeeTires on page 5-76andInflation - Tire Pressure on
page 5-77for more information on proper tire inflation.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need new tires.
Replace your tires when the tread depth is down to
1/8 of an inch (3.2 mm) for the front tires, or 1/16 of an
inch (1.6 mm) for a rear tire. Also, you need a new
tire if:
•You can see cord or fabric showing through the
tire’s rubber.
•The tread or sidewall is cracked, cut, or snagged
deep enough to show cord or fabric.
•The tire has a bump, bulge, or split.
•The tire has a puncture, cut, or other damage that
cannot be repaired well because of the size or
location of the damage.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if your
vehicle has one. Multiple conditions affect how fast this
aging takes place, including temperatures, loading
conditions, and inflation pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
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Sheet Metal Damage
If the vehicle is damaged and requires sheet metal
repair or replacement, make sure the body repair shop
applies anti-corrosion material to parts repaired or
replaced to restore corrosion protection.
Original manufacturer replacement parts will provide the
corrosion protection while maintaining the vehicle
warranty.
Finish Damage
Any stone chips, fractures or deep scratches in the
finish should be repaired right away. Bare metal
will corrode quickly and may develop into major repair
expense.
Minor chips and scratches can be repaired with touch-up
materials available from your dealer/retailer. Larger
areas of finish damage can be corrected in your
dealer’s/retailer’s body and paint shop.
Underbody Maintenance
Chemicals used for ice and snow removal and dust
control can collect on the underbody. If these are not
removed, corrosion and rust can develop on the
underbody parts such as fuel lines, frame, floor pan,
and exhaust system even though they have corrosion
protection.
At least every spring, flush these materials from the
underbody with plain water. Clean any areas where mud
and debris can collect. Dirt packed in close areas of
the frame should be loosened before being flushed.
Your dealer/retailer or an underbody car washing system
can do this.
Chemical Paint Spotting
Some weather and atmospheric conditions can create a
chemical fallout. Airborne pollutants can fall upon and
attack painted surfaces on the vehicle. This damage can
take two forms: blotchy, ring-shaped discolorations, and
small, irregular dark spots etched into the paint surface.
Although no defect in the paint job causes this, we will
repair, at no charge to the owner, the surfaces of
new vehicles damaged by this fallout condition within
12 months or 12,000 miles (20 000 km) of purchase,
whichever occurs first.
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Fuse Usage
1 Stoplamps
2 Not Used
3 Parking Lamps
4 Powertrain Control Module
5 Auxiliary Wiring
6 Heater/Air Conditioning
7 Hazard Warning Flashers
8 Power PostFuse Usage
9 Courtesy Lamps
10Warning Lights, Gages and
Indicators
11 Starter
12 Rear Axle/Four-Wheel-Drive
13Trailer Turn Signals/Hazard Warning
Flashers
14 Radio/Chime
15 Daytime Running Lamps
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Fuse Usage
PCM-B Powertrain Control Module
TCM Transmissions (LF8)
ENG 4 Engine 4 (LMM/LF6/LF8)
ENG 2 Engine 2 (L18/LMM)
HTD FUEL Heated Fuel (LMM)
BLANK Not Used
BLANK Not Used
NOTE 3 Fan Relay (LMM), Emissions (L18)
A/C COMP Air Conditioning Compressor
ABS 1 Antilock Brake System 1
ABS 2 Antilock Brake System 2
ABS 3 Antilock Brake System 3
ENGINE Engine
E/A PUMP Electronic/Automatic Pump
HORN Horn
NOTE 2Fuel (L18/LMM), Electronic Control
Module (LF6)Fuse Usage
NOTE 4 Electronic Control Module (LF6)
STUD A Spare
STUD B Spare
Relay Usage
NOTE 1 LMM/L18 Fuel Pump Relay
IGN B RELAY Ignition Relay
STARTER
RELAYStarter Relay
HORN RELAY Horn Relay
IGN A RELAY Ignition Relay
PTO/ECU*
RELAYPower Take-Off/Engine Control Unit
(*Diesel 7.8L LF8)
REVERSE
RELAYReverse Relay
FAN RELAY Fan Relay (LMM)
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Capacities and Specifications
The following approximate capacities are given in English and metric conversions. SeePart C: Recommended Fluids
and Lubricants on page 6-31for more information.
ApplicationCapacities
English Metric
Air Conditioning Refrigerant R134aFor the air conditioning system refrigerant charge
amount, see the refrigerant caution label located
under the hood. See your dealer/retailer for more
information.
Cooling System – C4/C5 Models
6.6L V8 Automatic Transmission 27.9 qt 26.4 L
8.1L V8 Automatic Transmission 29.8 qt 28.2 L
8.1L V8 Manual Transmission 30.1 qt 28.5 L
Cooling System – C6/C7/C8 Automatic Transmission
7.2L L6 Engine 32.0 qt 30.2 L
Isuzu 6H Engine (207 - 275 hp) 34.8 qt 32.9 L
Isuzu 6H Engine (300 hp) 33.9 qt 32.1 L
8.1L V8 Engine 32.5 qt 30.8 L
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Engine Drive Belt Routing
A. Air Conditioning Compressor.
B. Dual Generators.A. Air Conditioning Compressor.
B. Air Brake Compressor. 8.1L V8 Engine (C4, C5)
8.1L V8 Engine (C6,C7,C8)
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A. Dual Generators. A. Air Conditioning Compressor.6.6L V8 Duramax Diesel Engine
Isuzu 6H Diesel Engine
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