
Cooling System Capacity
The following approximate capacities are given in English and metric conversions. Please refer toPart C:
Recommended Fluids and Lubricants on page 6-29for more information.
ApplicationCapacities
English Metric
C4/C5 Models
8.1L with manual transmission 30.1 quarts 28.5 liters
8.1L with automatic transmission 29.8 quarts 28.2 liters
6.6L with manual transmission 27.6 quarts 26.1 liters
6.6L with automatic transmission 27.3 quarts 25.8 liters
C6/C7/C8 Models
8.1L with manual transmission 33.3 quarts 31.5 liters
8.1L with manual transmission, air conditioning and
increased cooling34.9 quarts 33.0 liters
8.1L with automatic transmission 32.5 quarts 30.8 liters
7.8L 200–230 hp engine with manual transmission 31.6 quarts 29.9 liters
7.8L 200–230 hp engine with manual transmission, air
conditioning and increased cooling35.3 quarts 33.4 liters
C6/C7/C8 Models
7.8L 200–215 hp engine with automatic transmission 33.7 quarts 31.9 liters
7.2L 175–230 hp engine with manual transmission 29.3 quarts 27.7 liters
5-94

ApplicationCapacities
English Metric
7.2L 175–230 hp engine with manual transmission, air
conditioning and increased cooling33.0 quarts 31.2 liters
7.2L 175–210 hp engine with automatic transmission 31.4 quarts 29.7 liters
7.8L 250–275 hp engine with manual transmission 34.9 quarts 33.0 liters
7.8L 250–275 hp engine with manual transmission, air
conditioning and increased cooling35.4 quarts 33.5 liters
7.8L 230–275 hp engine with automatic transmission 33.3 quarts 31.5 liters
7.2L 250–300 hp engine with manual transmission 32.8 quarts 31.0 liters
7.2L 250–300 hp engine with manual transmission, air
conditioning and increased cooling33.3 quarts 31.5 liters
7.2L 250–300 hp engine with automatic transmission 31.2 quarts 29.5 liters
Air Conditioning Refrigerant R134a 2.1 lbs. 1.0 kg
It is recommended that service work on your air conditioning system be performed by a qualified technician.
R134a 2.1 lbs. (1.0 kg)
Use Refrigerant Oil, R143a Systems
5-95

Transmission Fluid Capacity
For manual transmissions, the correct fluid level is to the bottom of the fluid fill plug opening. The fluid capacity will
vary, due to the angle of the transmission, with the vehicle. For automatic transmissions, see the Allison Automatic
Transmission Operator’s Manual for fluid check and maintenance information.
ApplicationCapacities
English Metric
Manual Transmission
ZF S6–650 12.7 pints 6.0 liters
RT6609 12.5 pints 5.9 liters
RT8709B 25.1 pints 11.8 liters
FS4205A, FS4205B, FS4205C 11.1 pints 5.3 liters
FS5205A, FS5205C 11.6 pints 5.5 liters
FS5406 18.4 pints 8.7 liters
FS6305A, FS6305B 18.4 pints 8.7 liters
FS6406 18.4 pints 8.7 liters
FS8406 18.5 pints 8.8 liters
RT8908LL 29.1 pints 13.8 liters
Automatic Transmission
MD 3060 P 52.0 pints 24.6 liters*
MD 3560 P 52.0 pints 24.6 liters*
1000 Series 35.0 pints 13.5 liters*
2000 Series 35.0 pints 13.5 liters*
2200 Series 35.0 pints 13.5 liters*
2400 Series 35.0 pints 13.5 liters*
*Add two pints (one liter) when changing spin-on or remote filter.
5-98

300,000 Miles (480 000 km)
❑Remove, disassemble, clean and inspect the air
brake air dryer (or every 3 years, or 10,800 hours,
whichever occurs first). Replace desiccant on
Bendix-Westinghouse units.
Footnotes
† = The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle’s useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
(1)= If your vehicle has an Allison automatic
transmission, your GM owner’s manual is supplemented
by an Allison Transmission
®Operator’s Manual.
Always refer to these manuals for related maintenance
services.
(2)= Refer to the Caterpillar
®Diesel Engine Operation
and Maintenance Manual for oil recommendations
and change intervals.
(3)= An Emission Control Service.
(4)= A Noise Emission Control Device.
(5)= Applies only to vehicles sold in the United States.(6)= Check fluid level in brake master cylinder, power
steering pump, axle, transmission and hydraulic
spring parking brake pump (if equipped). A low fluid
level in the brake master cylinder can indicate
worn brake linings and should be checked accordingly.
(7)= Inspect brake lines and hoses for proper
hook-up, binding, leaks, cracks, chafing, etc. Inspect
disc brake pads for wear and rotors for surface
condition. Inspect caliper assemblies. Check brake
pedal for excessive free play or travel (or every
6 months, whichever occurs first) and have serviced if
needed. Check brakes more often if driving habits
and conditions result in frequent braking.
(8)= Inspect parking brake drum and linings for wear or
cracks and check linkage and adjustment.
(9)= This vehicle has the GM Oil Life System. This
system will show you when to change the engine oil and
filter – usually between 3,000 miles (5 000 km) and
7,500 miles (12 000 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 000 km) or 12 months
without an oil and filter change.
Remember to reset the Oil Life System whenever the oil
is changed. For more information, seeChange Engine
Oil Light on page 3-39.
6-19

Starter Switch Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular
brakes. See “Parking Brake” if necessary.
Do not use the accelerator pedal, and be ready to
turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only
in PARK (P), if equipped, or NEUTRAL (N). If
the starter works in any other position, your vehicle
needs service.
Automatic Transmission Shift Indicator
Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is
harder to turn or has too much free play, or if there are
strange sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or for
the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
Engine Cooling System Service
Inspect the hoses and have them replaced if they are
cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-26

Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number or specification may be obtained from your
dealer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets GM
Standard GM6094M and displays
the American Petroleum Institute
Certified for Gasoline Engines
starburst symbol. To determine the
proper viscosity for your vehicle’s
engine, see “Engine Oil” in the
Index.
Engine Oil
(DURAMAX™
Diesel Engine)Engine oil with the letters CI-4 or
CH-4 is best for your vehicle. The
CI-4 or CH-4 designation may
appear either alone or in
combination with other API
designations, such as API CI-4/SL.
These letters show American
Petroleum Institute levels of quality.
To determine the preferred viscosity
for your vehicle’s diesel engine, see
“Engine Oil” in the Index.
Usage Fluid/Lubricant
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX™
Diesel)50/50 mixture of clean, drinkable
water and use only
DEX-COOL
®Coolant. See “Engine
Coolant” in the Index.
Hydraulic Brake
SystemDelco Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventGM Optikleen
®Washer Solvent.
Clutch Bearing
LubricantClutch Bearing Lubricant (GM Part
No. 12378484 or equivalent NLGI #3
consistency).
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease (GM Part
No. U.S. 1051344, in Canada
903037) or NLGI #3 consistency.
Power Steering
SystemDEXRON
®-III Automatic
Transmission Fluid.
6-29

Usage Fluid/Lubricant
Manual
Transmission
(Except ZF
6–Speed)Synthetic Manual Transmission Fluid
(GM Part No. U.S. 12345724, in
Canada 10953510).
Manual
Transmission
(ZF 6–Speed)TranSynd™ Synthetic Transmission
Fluid (GM Part No. U.S. 12378515,
in Canada 88900701).
Automatic
TransmissionSee the Allison
Transmission
®Operator’s Manual for
correct transmission fluid.
Key Lock
CylindersMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
Chassis
LubricationChassis Lubricant (GM Part No. U.S.
12377985, in Canada 88901242) or
lubricant meeting requirements of
NLGI #2, Category LB or GC-LB.
Front Wheel
Bearing Grease
(Except Oil
Filled Hubs)Wheel bearing lubricant meeting
requirements of NLGI #2, Category
GC or GC-LB (GM Part No. U.S.
1051344, in Canada 993037).
Usage Fluid/Lubricant
Front Wheel
Bearing Grease
with Oil Filled
HubsSAE 75W-90 Synthetic Axle
Lubricant for Medium Duty Trucks
(GM Part No. U.S. 12345841, in
Canada 10953512t).
Rear Axle and
Rear HubsSAE 75W-90 Synthetic Axle
Lubricant for Medium Duty Trucks
(GM Part No. U.S. 12345841, in
Canada 10953512).
Rear Axle Shift
Motor LubricantRefrigerant Oil (GM Part No.U.S.
5416939, in Canada 10953496).
Propshafts and
SplinesWheel bearing lubricant meeting
requirements of NLGI #2, Category
GC or GC-LB (GM Part No. U.S.
1051344, in Canada 993037).
Cab — Door
Hinges and
LatchesMulti-Purpose Lubricant, Superlube
(GM Part No. U.S. 12346241, in
Canada 10953474).
Weatherstrip
ConditioningDielectric Silicone Grease (GM Part
No. U.S. 12345579, in Canada
992887).
Weatherstrip
SqueaksSynthetic Grease with Teflon,
Superlube (GM Part No. U.S.
12371287, in Canada 10953437).
6-30

A
Accessory Power Outlets.................................3-17
Adding Equipment to Your Air Bag-Equipped
Vehicle.......................................................1-61
Adding Washer Fluid.......................................5-44
Additives, Fuel................................................. 5-7
Add-On Electrical Equipment............................5-86
Adjusting the Speakers
(Balance/Fade)............................3-47, 3-50, 3-54
Air Bag
Off Light.....................................................3-28
Readiness Light..........................................3-27
Air Bag System..............................................1-48
Adding Equipment to Your Air Bag-Equipped
Vehicle...................................................1-61
Air Bag Off Switch.......................................1-55
How Does an Air Bag Restrain?....................1-53
Servicing Your Air Bag-Equipped Vehicle.........1-60
What Makes an Air Bag Inflate?....................1-53
What Will You See After an Air Bag Inflates? . . 1-54
When Should an Air Bag Inflate?...................1-53
Where Are the Air Bags?..............................1-52
Air Brake.......................................................2-35
Air Brake System Warning Light........................3-33
Air Brake Systems..........................................5-50
Air Cleaner/Filter, Engine.................................5-30
Air Conditioning System...................................5-67Air Connections..............................................4-36
Air Dryer.......................................................5-50
Air Pressure Gage..........................................3-44
Air Shift Control (Automatic Transmission)..........2-27
Air Suspension...............................................2-27
Air Suspension Seats........................................ 1-6
Airbag Sensing and Diagnostic Module (SDM)...... 7-5
All Overseas Locations...................................... 7-4
Allison Transmission
®External Filters...............5-100
Aluminum or Chrome-Plated Wheels..................5-82
AM ...............................................................3-57
AM-FM Radio.................................................3-46
Antenna, Fixed Mast.......................................3-59
Anti-lock Brake System (ABS)............................ 4-7
Anti-Lock Brake, System Warning Light..............3-34
Anti-Lock Brakes, Trailer System
Warning Light.............................................3-35
Appearance Care............................................5-76
Care of Safety Belts....................................5-79
Chemical Paint Spotting...............................5-83
Cleaning the Inside of Your Vehicle................5-77
Cleaning the Outside of Your Vehicle..............5-80
Finish Damage............................................5-83
Sheet Metal Damage...................................5-82
Underbody Maintenance...............................5-83
Vehicle Care/Appearance Materials................5-84
Weatherstrips..............................................5-79
Ashtrays........................................................3-18
1