Page 391 of 497

6-26
Automatic Transmission Fluid
(Allison Only)
When to Check and Change
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 25,000 miles
(41 500 km) if the vehicle is mainly driven under one or
more of these conditions:
In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of
these conditions, change the fluid and filter
every 50,000 miles (83 000 km).
See ªScheduled Maintenance Servicesº in the Index.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership service department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
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
you check your transmission fluid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
When outside temperatures are above 90F (32C).
At high speed for quite a while.
In heavy traffic
-- especially in hot weather.
While pulling a trailer.
Page 394 of 497

6-29
NOTICE:
We recommend you use only fluid labeled
DEXRON-III, because fluid with that label is
made especially for your automatic transmission.
Damage caused by fluid other than
DEXRON
-III is not covered by your new
vehicle warranty.
After adding fluid, recheck the fluid level as
described under ªHow to Check.º
When the correct fluid level is obtained, push the
dipstick back in all the way.
Manual Transmission Fluid
When to Check
A good time to have it checked is when the engine oil is
changed. See your maintenance schedule to find out
when to change your transmission fluid.
How to Check
Because this operation can be a little difficult, you
may choose to have this done at your GM dealership
service department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading.
NOTICE:
Too much or too little fluid can damage your
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
you check your transmission fluid.
Check the fluid level only when your engine is off, the
vehicle is parked on a level place and the transmission is
cool enough for you to rest your fingers on the
transmission case.
Page 449 of 497

6-84
Fuse Usage
B/U LP Backup Lamps, Automatic
Transmission Shift Lock
Control System
ATC Automatic Transfer Case
RR DEFOG Rear Window Defogger,
Heated Mirrors (Relay)
RR PRK Right Rear Parking Lamps
ECM B PCM
F/PMP Fuel Pump (Relay)
O2 A Oxygen Sensors
FUEL HT Fuel Heater, Glow Plug and Intake
Heater Controls
O2 B Oxygen Sensors
LR PRK Left Rear Parking Lamps
RR DEFOG Rear Window Defogger,
Heated Mirrors
HDLP Headlamps (Relay)
TRL PRK Parking Lamps Trailer Wiring
RT HDLP Right Headlamps
DRL Daytime Running Lamps (Relay)
HTD MIR Heated MirrorsFuse Usage
LT HDLP Left Headlamps
A/C Air Conditioning
AUX PWR Cigarette Lighter, Auxiliary
Power Outlets
SEO 2 Special Equipment Option Power,
Power Seats, Aux Roof Mnt Lamp
SEO 1 Special Equipment Option Power,
Aux Roof Mnt Lamp, Cell
Phone, OnStar
DRL Daytime Running Lamps
A/C A/C (Relay)
FOG LP Fog Lamps
FOG LP Fog Lamps (Relay)
RADIO Audio System, Instrument Cluster,
Climate Control System
CIGAR Cigarette Lighter, Auxiliary
Power Outlets
RT TURN Right Turn Signals
BTSI Automatic Transmission Shift
Lock Control System
LT TURN Left Turn Signals
FR PRK Front Parking Lamps,
Sidemarker Lamps
Page 452 of 497
6-87 Cooling System Capacity
After refill, the level must be rechecked. See ªCooling Systemº in the Index.
Engine Transmission Quantity
VORTEC 4300 V6 Automatic 12.6 quarts (11.9 L)
VORTEC 4300 V6 Manual 12.9 quarts (12.2 L)
VORTEC 4800 V8 Automatic 13.4 quarts (12.7 L)
VORTEC 4800 V8 Manual 13.7 quarts (13.0 L)
VORTEC 5300 V8 Automatic 13.4 quarts (12.7 L)
VORTEC 5300 V8** Automatic 14.9 quarts (14.1 L)
VORTEC 6000 V8 Automatic 14.8 quarts (14.0 L)
VORTEC 6000 V8* Automatic 14.4 quarts (13.6 L)
VORTEC 6000 V8 Manual 15.2 quarts (14.4 L)
VORTEC 6000 V8* Manual 14.8 quarts (14.0 L)
VORTEC 8100 V8 Manual 21.1 quarts (20.0 L)
VORTEC 8100 V8 Automatic 20.7 quarts (19.6 L)
* Vehicles equipped with the optional engine oil cooler.
** Vehicles equipped with the optional air conditioner.
Page 465 of 497

Scheduled Maintenance
7-10
25,000 Miles (41 500 km)
Allison Transmission Only: Change automatic transmission fluid and filters if
the vehicle is mainly driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly
reaches 90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions, change the fluid
and filter every 50,000 miles (83 000 km).
30,000 Miles (50 000 km)
If Equipped: Replace passenger compartment air filter. If you drive regularly
under dusty conditions, the filter may require replacement more often.
Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking.
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
Replace fuel filter.
An Emission Control Service. (See footnote .)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE
Page 467 of 497

Scheduled Maintenance
7-12
50,000 Miles (83 000 km)
Change automatic transmission fluid and filter if the vehicle's GVWR is over
8600 lbs., if the vehicle has an Allison transmission or if the vehicle is mainly
driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly
reaches 90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
Except Allison Transmission: If you do not use your vehicle under any of these
conditions, change the fluid and filter at 100,000 miles (166 000 km).
Automatic Transfer Case Only: Change transfer case fluid.
52,500 Miles (87 500 km)
Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking.
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.)
ACTUAL
SERVICED BY:MILEAGE
DATE
ACTUAL
SERVICED BY:MILEAGE
DATE
Page 469 of 497
Scheduled Maintenance
7-14
75,000 Miles (125 000 km)
If Equipped: Replace passenger compartment air filter. If you drive regularly
under dusty conditions, the filter may require replacement more often.
Check rear/front axle fluid level and add fluid as needed. Check constant
velocity joints and axle seals for leaking.
Allison Transmission Only: Change automatic transmission fluid and filter if
the vehicle is mainly driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly
reaches 90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of these conditions, change the fluid
and filter every 50,000 miles (83 000 km).
Rotate tires. See ªTire Inspection and Rotationº in the Index for proper
rotation pattern and additional information. (See footnote +.) ACTUAL
SERVICED BY:MILEAGE
DATE
Page 471 of 497
Scheduled Maintenance
7-16
100,000 Miles (166 000 km)
Inspect spark plug wires.
An Emission Control Service.
Replace spark plugs.
An Emission Control Service.
Change automatic transmission fluid and filter if the vehicle's GVWR is over
8600 lbs., if the vehicle has an Allison transmission or if the vehicle is mainly
driven under one or more of these conditions:
± In heavy city traffic where the outside temperature regularly
reaches 90F (32C) or higher.
± In hilly or mountainous terrain.
± When doing frequent trailer towing.
± Uses such as found in taxi, police or delivery service.
If you haven't used your vehicle under severe service conditions listed
previously and, therefore, haven't changed your automatic transmission fluid,
change both the fluid and filter.
Automatic Transfer Case Only: Change transfer case fluid.
Except 8.1L V8 Engine: Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service. ACTUAL
SERVICED BY:MILEAGE
DATE