Page 328 of 386
6-74
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 a major repair expense.
Minor chips and scratches can be repaired with touch
-up
materials available from your dealer or other service
outlets. Larger areas of finish damage can be corrected
in your dealer'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, accelerated corrosion (rust) can occur 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 other debris can collect. Dirt packed in closed areas
of the frame should be loosened before being flushed.
Your dealer or an underbody vehicle washing system
can do this for you.
Page 330 of 386

6-76
Vehicle Identification Number (VIN)
This is the legal identifier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on the
driver's side. You can see it if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certification and Service Parts
labels and the certificates of title and registration.
Engine Identification
The 8th character in your VIN is the engine code. This
code will help you identify your engine, specifications
and replacement parts.
Service Statement
One of these statements is on your GVW Rating label.
Here is what each one means.
TRUCK SERVICE
-- A vehicle made to carry
property or special equipment. It is made for uniform
frame loading. That includes using the vehicle to pull a
full trailer.
TRUCK
-TRACTOR -- A vehicle made to draw other
vehicles. It's made to carry part of the load of the trailer.
It is made for point frame loading, usually for a
semi
-trailer (ªfifth wheelº).
MAX. VERT. CG
-- The highest allowable vertical
center of gravity, at the highest allowable GVWR. It's
measured from level ground in inches.
TRUCK
-CANADA -- A vehicle first sold in Canada
with a non
-school bus application, or cab models with
regular production option RQ2 (ªtruck serviceº).
TRACTOR
-CANADA -- A cab model with regular
production option RQ3 (ªtruck
-tractor serviceº).
Page 331 of 386
6-77
Service Parts Identification Label
You'll find this label in a location determined by the
body manufacturer. It's very helpful if you ever need to
order parts. On this label is:
your VIN,
the model designation,
paint information and
a list of all production options and special
equipment.
Be sure that this label is not removed from the vehicle.
Electrical System
Add-On Electrical Equipment
NOTICE:
Don't add anything electrical to your vehicle
unless you check with your dealer first. Some
electrical equipment can damage your vehicle
and the damage wouldn't be covered by your
warranty. Some add
-on electrical equipment
can keep other components from working as
they should.
Page 344 of 386

6-90 Rear Axle Lubricant Capacity
Single Speed Axle Pints (Liters). . . . . . . . . . . . . . . .
80 10.0 (4.7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
S135 26.0 (12.3). . . . . . . . . . . . . . . . . . . . . . . . . . . .
19060S 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . .
21060D 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . .
21060S 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . . . . . .
S150 28.0 (13.0). . . . . . . . . . . . . . . . . . . . . . . . . . . .
23090S 40.0 (19.0). . . . . . . . . . . . . . . . . . . . . . . . . .
23105S 56.0 (26.5). . . . . . . . . . . . . . . . . . . . . . . . . .
26105S 54.0 (25.5). . . . . . . . . . . . . . . . . . . . . . . . . .
Tw o
-Speed Axle Pints (Liters). . . . . . . . . . . . . . . . .
19060T 38.0 (18.0). . . . . . . . . . . . . . . . . . . . . . . . . .
21060T 38.0 (18.0). . . . . . . . . . . . . . . . . . . . . . . . . .
23082T 40.0 (19.0). . . . . . . . . . . . . . . . . . . . . . . . . .
26080T 44.0 (20.8). . . . . . . . . . . . . . . . . . . . . . . . . .
Tandem Axles Pints (Liters). . . . . . . . . . . . . . . . . . .
DS344 (front) 32.0 (15.1). . . . . . . . . . . . . . . . . . . . .
RS344 (rear) 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . .
DSH44 (front) 32.0 (15.1). . . . . . . . . . . . . . . . . . . . .
RSH44 (rear) 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . .
DS404, DS404P (front) 32.0 (15.1). . . . . . . . . . . . . .
RS404 (rear) 31.0 (14.7). . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Refrigerant
Capacity
If you do your own service work, you'll need the proper
service manual. See ªDoing Your Own Service Workº in
the Index for additional information. It is recommended
that service work on your air conditioning system be
performed by a qualified technician.
Air Conditioning Refrigerant
R134a 2.1 lbs. (1.0 kg). . . . . . . . . . . . . . . . . . . . . . .
Use Refrigerant Oil, R143a Systems
Normal Maintenance
Replacement Parts
Allison Transmission External Filters
See the Allison Transmission Operator's Manual in your
vehicle for external filter part numbers and information.
Air Compressor Filter
Air Compressor Part Number
Bendix Tu
-Flo
550 (13.2 CFM)2467368
Page 345 of 386
6-91 Service Replacement Part and Filter Recommendations
Engine 7.2L 8.1L 7.8L 6.6L
RPO LG5 L18 LG4 LB7
Spark Plug
ACDelco
41-983
Gap 0.060 inch (1.52 mm)
Torque 14.75 lb. ft. (20.0 Nm)
Oil Filter
CAT
1R0739 ACDelco PF454GM Part No. 94392475
ACDelco PF1218
Air Cleaner Donaldson P522606
ACDelco
A1518CC4/C5 Models:
GM Part No. 88937527
C6/C7/C8 Models:
GM Part
No. 88937548***C4/C5 Models:
GM Part No. 88937527
C6/C7/C8 Models:
GM Part No. 88937548***
Fuel Filter
ACDelco
915 Primary**ACDelco GF626*GM Part No. 94392474 GM Part No. 97256734
Page 347 of 386
7-
7-1
Section 7 Maintenance Schedule
This section covers the maintenance required for your vehicle. Your vehicle needs these services to retain its safety,
dependability and emission control performance.
7
-2 Introduction
7
-4 Part A: Scheduled Maintenance Services
7
-5 Scheduled Maintenance7
-21 Part B: Owner Checks and Services
7
-27 Part C: Recommended Fluids and Lubricants
7
-30 Part D: Maintenance Record
Page 349 of 386

7-3 How This Section is Organized
This maintenance schedule is divided into four parts:
ªPart A: Scheduled Maintenance Servicesº explains
what to have done and how often. Some of these
services can be complex, so unless you are technically
qualified and have the necessary equipment, you should
let your dealer's service department or another qualified
service center do these jobs.
CAUTION:
Performing maintenance work on a vehicle can
be dangerous. In trying to do some jobs, you can
be seriously injured. Do your own maintenance
work only if you have the required know
-how
and the proper tools and equipment for the job.
If you have any doubt, have a qualified
technician do the work.
If you want to get the service information, see ªService
and Owner Publicationsº in the Index.ªPart B: Owner Checks and Servicesº tells you
what should be checked and when. It also explains what
you can easily do to help keep your vehicle in good
condition.
ªPart C: Recommended Fluids and Lubricantsº lists
some recommended products necessary to help keep
your vehicle properly maintained. These products, or
their equivalents, should be used whether you do the
work yourself or have it done.
ªPart D: Maintenance Recordº is a place for
you to record and keep track of the maintenance
performed on your vehicle. Keep your maintenance
receipts. They may be needed to qualify your vehicle
for warranty repairs.
Page 350 of 386

7-4
Part A: Scheduled Maintenance
Services
Using Your Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good working condition. But we don't know
exactly how you'll drive it. You may drive very short
distances only a few times a week. Or you may drive
long distances all the time in very hot, dusty weather.
You may use your vehicle in making deliveries or in
many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements. So please read the
following and note how you drive. If you have any
questions on how to keep your vehicle in good
condition, see your dealer.
This part tells you the maintenance services you should
have done and when you should schedule them. If you
go to your dealer for your service needs, you'll know
that GM
-trained and supported service people will
perform the work using genuine GM parts.The proper fluids and lubricants to use are listed in
Part C. Make sure whoever services your vehicle uses
these. All parts should be replaced and all necessary
repairs done before you or anyone else drives
the vehicle.
This schedule is for vehicles that:
carry passengers and cargo within recommended
limits. You will find these limits on your vehicle's
GVW Rating label. See ªLoading Your Vehicleº in
the Index.
are driven on reasonable road surfaces within legal
driving limits.
use the recommended fuel. See ªFuelº in the Index.
Scheduled Maintenance Supplements
If your vehicle has a Caterpillar diesel engine, your
owner's manual is supplemented by the Caterpillar
Diesel Engine Operation & Maintenance Manual. If
your vehicle has an Allison transmission, your owner's
manual is supplemented by an Allison Transmission
Operator's Manual. Always refer to these manuals for
related maintenance services.