1993 GMC SIERRA Section 7

6.2L AND 6.5L DIESEL ENGINES-
-0OTNOTES:
rt Change filter every 15,000 miles (24 000 km), except when operating in dusty
conditions. Dusty conditions may require more frequent filter re\
placement. Extreme
dust and dirt operating conditions (off-road), may require the air filter
to be
checked as often as every 300 miles (483 km) and replaced as necessary.
* An Emission Control Service
** See “Explanation of Scheduled Maintenance Services” in this section.
1 Applicable only to trucks sold in the United States.
A Also, a Noise Control Service (applicable to vehicles with engine VIN Code J).
t This maintenance schedule applies to all diesel engines available. TO330
7-1 4
ProCarManuals.com

Scheduled Maintenance Services
6.2L AND 6.5L DIESEL ENGINES-
If your driving conditions meet those specified in “Scheduled Ma\
intenance Services” in this section, use Maintenance Schedule
I (4.
7-1 6
ProCarManuals.com

Scheduled Maintenance Services
Explanation Of Scheduled Maintenance Services
Below are explanations of the services listed in the maintenance charts.
The proper fluids and lubricants to use are listed in this section. 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 ve\
hicle.
1.
ENGINE OIL AND OIL FILTER CHANGE* -ALWAYS USE SG OR
SGKE QUALITY, ENERGY CONSERVING II OILS OF THE PROPER
VISCOSITY. To determine the preferred viscosity oil for your vehicle’s
engine (e.g. SAE 5W-30 or 10W-30), see “Engine Oil” in the Index.
2. CHASSIS LUBRICATION -Lubricate the front suspension, king pin
bushings, steering linkage, transmission, and transfer case shift\
linkage,
parking brake cable guides, propshaft splines (2 wheel drive), brake
pedal springs, and clutch pedal springs at the intervals specified.
If you have a 3500 HD, lubricate the king pins and king pin bushings
every 1,500 miles
(2500 km) for Maintenance Schedule 1, or every 3,000
(5000 km) for Maintenance Schedule 2.
Ball joints and king pin bushings should not be lubricated unless their
temperature is
10°F (-12”C), or higher. When the weather is cold, let
them warm up before lubrication or they could be damaged.
Also, be sure to check
all the vehicle fluid levels at this time.
3.
CLUTCH FORK BALL STUD LUBRICATION -Lubricate the clutch fork
ball stud through the fitting on the clutch housing. Lubricant must be
added “sparingly” to the fitting, as only.
0066 Ib. (.003 kg) is required to
lubricate the ball stud surface.
Do not add lubricant more often than the
intervals in the Maintenance Charts.
Too much lubricant will damage
the clutch assembly.
4. ENGINE IDLE SPEED ADJUSTMENT (DIESEL ENGINES)* -Adjust to
the specifications shown on the underhood label. You must use
calibrated test equipment.
5. COOLING SYSTEM SERVICE* -Drain, flush and refill system with new
coolant. See “Engine Coolant’’ in the Index for the proper coolant and
mixture to use in your vehicle.
Also inspect the hoses and replace them
if they are cracked, swollen, or
deteriorated. Tighten all hose clamps (except constant tension \
clamps).
Remove debris and clean the outside
of the radiator and air conditioning
condenser. Wash the radiator neck.
To ensure proper operation, pressure
test the radiator and cap.
* An Emission Control Service
7-1
8
ProCarManuals.com

6. AIR CLEANER FILTER REPLACEMENT* -Replace at every 30,000
miles (50 000 km) or more often under dusty conditions. Ask your dealer
for the proper replacement intervals for your driving conditions\
.
7. FRONT WHEEL BEARING REPACK (2 WHEEL DRIVE ONLY) -Clean
and repack the front wheel bearings at each brake relining, or\
at the specified interval, whichever comes first.
8.
TRANSMISSION SERVICE
Automatic Transmission
-Change the transmission fluid and filter every
15,000 miles (25 000 km) for vehicles under 8,600 GVWR or every
12,000 miles (20 000 km) for vehicles over 8,600 GVWR if the vehicle
is mainly driven under one or more of these conditions:
In heavy city traffic.
Where the outside temperature regularly reaches 90°F (32°C\
) or
higher.
In hilly or mountainous terrain.
Frequent trailer pulling.
Uses such as taxi, police, delivery or other commercial service\
.
If the vehicle is not used mainly under any of these conditions, change
the fluid and filter every 30,000 miles
(50 000 km) for vehicles under
8600 GVWR or every
24,000 miles (40 000 km) for vehicles over 8600
GVWR. See “Automatic Transmission Fluid” in the Index for more
information.
Manual Transmission -Transmission fluid does not require periodic
changing.
Regulator Valve System for any worn, plugged or collapsed hoses. Have
the system checked as described in the Service Manual.
9.
CDRV SYSTEM INSPECTION* -Check
the Crankcase Depression
10. FUEL FILTER REPLACEMENT* -Replace the fuel filter at the specified
interval
or sooner if clogged.
11. SPARK PLUGS REPLACEMENT* -Replace spark plugs with the type
listed in Section
6. See “Specification Charts” in the Index.
12.
SPARK PLUG WIRE INSPECTION* -Clean wires and inspect for burns,
cracks or other damage. Check the wire boot fit at the distributor and at
the spark plugs. Replace wires as needed.
*An Emission Control Service
7-1 9
ProCarManuals.com

23. EXHAUST PRESSURE REGULATOR VALVE INSPECTION* -Check that
the valve works properly. Correct any binding. Inspect hoses fo\
r cracks, chafing or decay. Replace parts as needed.
24.
TIRE AND WHEEL ROTATION AND INSPECTION -For proper wear
and maximum tire life, rotate tires at the first
6,000 miles (1 0 000
kilometers) for Schedule I (t) or 7,500 miles (12 500 kilometers) for
Schedule
II (.) and then every 15,000 miles (25 000 kilometers)
thereafter. Follow the instructions and patterns shown in Section 6.
Check tires for uneven wear or damage.
If irregular or premature wear is
apparent, check wheel alignment. Also, check for damaged wheels.\
See
“Tires” in the Index for more information.
For dual wheels, whenever the vehicle, wheels, or fasteners are new,
have the wheel fastener torque set at the first 100,
1,000 and 6,000
miles (160, 1600 and 10
000 km).
For 3500 H.D. Models, block the tires opposite those being removed to
keep the vehicle from rolling.
25.
DRIVE AXLE SERVICE -Check readfront axle fluid level and add as
needed. Check constant velocity joints and axle seals for leaki\
ng.
Locking differential-Drain fluid at first oil change and refill. Check
fluid level and add as needed at subsequent oil changes.
In dusty
areas, or trailer towing applications drain fluid at every 15,0\
00 miles
(24 135 kilometers) and refill$
every oil change. In dusty areas, or trailer towing applications, drain
fluid every 15,000 miles
(24 135 kilometers) and refi1l.t
More frequent lubrication may be required on heavy-duty or off-road
use.
Standard differential -Check fluid level and add as needed at
26.
BRAKE SYSTEM INSPECTION -When the engine oil is changed,
inspect the lines and hoses for proper hookup, binding, leaks, \
cracks,
chafing, etc. Check the parking brake adjustment, and the fluid level in
the master cylinder.
A low fluid level can indicate worn disc brake pads
which may need to be sewiced.t
*An Emission Control Service
tA fluid
loss in these systems may indicate a problem. Have them
inspected and repaired at once.
7-2
1
ProCarManuals.com

Scheduled Maintenance Sewices
When the wheels are removed for rotation, inspect disc brake pads f\
or wear
and rotors for surface condition.
Also inspect drum brake linings for wear and
cracks. Inspect other brake parts, including drums, wheel cylind\
ers, parking
brake, etc., at the same time. Remove any rust
or dirt from the wheel and
mounting surfaces before mounting the wheel.
Inspect brakes more often if driving habits or conditions resull In
frequent braking.
Owner Checks and Services
Listed below are owner checks and services which should be mad\
e at the
time period specified
to help ensure proper safety, emission performance, and
dependability of your vehicle.
Be sure any necessary repairs are completed at once. Whenever \
any fluids
or lubricants are added to your vehicle, make sure they are the proper ones,
as shown
in this Section.
At Least Once a Month
Tire inflation pressure check -Check the tires for proper inflation. If they
are low, inflate them
to the level specified on the certification label or on the
tire inflation charts. See “Loading Your Vehicle’’ or “Inflation-Tire Pressure” in
the Index.
At Least Once a Year
Key lock cylinder lubrication -Lubricate key lock cylinders with engine oil.
See the “Recommended Fluid and Lubricants’’ chart in this section.
Transmission neutral or clutch start switch operation
CAUTION
~
1. Before you start, be sure you have enough room around the veh\
icle.
2. Firmly apply both the manual parking brake and the regular brake. See
“Brakes” and “Parking Brake” in the Index.
Do not use the accelerator
pedal.
3. Be ready to turn off the engine immediately if it starts.
4. On automatic transmission vehicles, try to start the engine in each gear.
The starter should work only in
P (Park) or N (Neutral).
7-22
ProCarManuals.com

Customer Assistance Information
i Section
Here you will find out how to contact GMC Truck if you need assistance.
This section also tells you
how to obtain service publications and how to
report any safety defects.
Customer Satisfaction Procedure
........................................................................\
. 8-2
Customer Assistance for HearinglSpeech Impaired
........................................... 8-3
GM Participation in Better Business Bureau MediatiodArbitration Program .... 8-3
Reporting Safety Defects
........................................................................\
.............. 8-4
Roadside Assistance ........................................................................\
.................... .8-5
Service Publications
........................................................................\
...................... 8-6
8-1
ProCarManuals.com

When contacting GMC Truck, please remember that your concern wi\
ll likely be resolved in the dealership, using the dealership’s facilit\
ies, equipment and personnel. That is why we suggest you follow Step One first
if you have a
concern.
Customer Assistance for the Hearing or
Speech Impaired (TDD)
To assist owners who have hearing difficulties, GMC Truck has inst\
alled
special TDD (Telecommunications Devices for the Deaf) equipment\
at its
Customer Assistance Center. Any hearing or speech impaired custo\
mer who
has access to a TDD or conventional teletypewriter (TTY) can \
communicate
with GMC Truck by dialing:
In the United States
..................................................................... 1 -800-GMC-TKTD
In Canada
........................................................................\
................. 1-800-263-3830.
GM Participation in Better Business
Bureau Mediation/Arbitration Program*
*This program may not be available in all states, depending on\
state law.
Canadian owners refer to your Warranty and Owner Assistance Inf\
ormation
booklet.
General Motors reserves the right to change eligibility limitati\
ons and/or to
discontinue its participation in this program.
Our experience has shown that the Customer Satisfaction Procedur\
e
described earlier in this section has been very successful in \
achieving
customer satisfaction. However,
if you have not been substantially satisfied,
GMC Truck wants you to be aware of GM’s voluntary participa\
tion in a
no-charge mediationlarbitration program called BBB AUTO LINE. This program
is administered by the Council of Better Business Bureaus through local
Better Business Bureaus. The program can resolve individual disp\
utes
involving vehicle repairs and the interpretation of your New Vehicle Limited
Warranty.
We prefer that you not resort to BBB AUTO LINE until after a fi\
nal .decision
is made under the Customer Satisfaction Procedure. However, you \
may file a
claim at any time by contacting your local Better Business Bur\
eau (BBB) at
the following toll-free number: 1-800-955-5100. For further infor\
mation about
filing a claim, you may also write to: BBB AUTO
LINE, Council of Better
Business Bureaus, 4200 Wilson Boulevard, Suite 800, Arlington, V\
irginia
22203.
8-3
ProCarManuals.com