
HOISTING
STANDARD PROCEDURE - HOISTING
Refer to the Owner's Manual for emergency vehicle
lifting procedures.
WARNING: THE HOISTING AND JACK LIFTING
POINTS PROVIDED ARE FOR A COMPLETE VEHI-
CLE. WHEN A CHASSIS OR DRIVETRAIN COMPO-
NENT IS REMOVED FROM A VEHICLE, THE
CENTER OF GRAVITY IS ALTERED MAKING SOME
HOISTING CONDITIONS UNSTABLE. PROPERLY
SUPPORT (Fig. 9) OR SECURE VEHICLE TO HOIST-
ING DEVICE WHEN THESE CONDITIONS EXIST.
FLOOR JACK
When properly positioned, a floor jack can be used
to lift a vehicle (Fig. 10). Support the vehicle in the
raised position with jack stands at the front and rear
ends of the frame rails (Fig. 9).CAUTION: Do not lift vehicle with a floor jack posi-
tioned under:
²An axle tube.
²A body side sill.
²A steering linkage component.
²A drive shaft.
²The engine or transmission oil pan.
²The fuel tank.
²A front suspension arm.
NOTE: Use the correct frame rail lifting locations
only (Fig. 11).
HOIST
A vehicle can be lifted with:
²A single-post, frame-contact hoist.
²A twin-post, chassis hoist.
²A ramp-type, drive-on hoist.
NOTE: When a frame-contact type hoist is used,
verify that the lifting pads are positioned properly
(Fig. 10). The forward lifting pads should be posi-
tioned a minimum of 5 inches forward of the cross-
member bolt access holes (Fig. 11).
Fig. 9 Safety Stands
1 - SAFETY STANDS
Fig. 10 Vehicle Lifting Locations
BR/BELUBRICATION & MAINTENANCE 0 - 9

TOWING
STANDARD PROCEDURE - TOWING
A vehicle equipped with SAE approved sling-type
towing equipment can be used to tow all vehicles.
When towing a 4WD vehicle using a wheel-lift towing
device, use tow dollies under the opposite end of the
vehicle. A vehicle with flat-bed device can also be
used to transport a disabled vehicle (Fig. 12).
A wooden crossbeam may be required for proper
connection when using the sling-type, front-end tow-
ing method.
SAFETY PRECAUTIONS
CAUTION: The following safety precautions must be
observed when towing a vehicle:
²Secure loose and protruding parts.
²Always use a safety chain system that is inde-
pendent of the lifting and towing equipment.
²Do not allow towing equipment to contact the
disabled vehicle's fuel tank.
²Do not allow anyone under the disabled vehicle
while it is lifted by the towing device.
²Do not allow passengers to ride in a vehicle
being towed.
²Always observe state and local laws regarding
towing regulations.
²Do not tow a vehicle in a manner that could
jeopardize the safety of the operator, pedestrians or
other motorists.²Do not attach tow chains, T-hooks, J-hooks, or a
tow sling to a bumper, steering linkage, drive shafts
or a non-reinforced frame hole.
²Do not tow a heavily loaded vehicle. Damage to
the cab, cargo box or frame may result. Use a flatbed
device to transport a loaded vehicle.
GROUND CLEARANCE
CAUTION: If vehicle is towed with wheels removed,
install lug nuts to retain brake drums or rotors.
A towed vehicle should be raised until lifted wheels
are a minimum 100 mm (4 in) from the ground. Be
sure there is adequate ground clearance at the oppo-
site end of the vehicle, especially when towing over
rough terrain or steep rises in the road. If necessary,
remove the wheels from the lifted end of the vehicle
and lower the vehicle closer to the ground, to
increase the ground clearance at the opposite end of
the vehicle. Install lug nuts on wheel attaching studs
to retain brake drums or rotors.
RAMP ANGLE
If a vehicle with flat-bed towing equipment is used,
the approach ramp angle should not exceed 15
degrees.
Fig. 11 Front Lift Pad Location
1 - SHIPPING TIE DOWN SLOT
2 - CROSSMEMBER BOLT ACCESS HOLE
3 - LIFTARM
4 - LIFT PAD EXTENSION
5 - FRAME RAIL
Fig. 12 Tow Vehicles With Approved Equipment
1 - SLING TYPE
2 - WHEEL LIFT
3 - FLAT BED
0 - 10 LUBRICATION & MAINTENANCEBR/BE
HOISTING (Continued)

SPECIAL TOOLS
SUSPENSION-REAR
BUSHINGS
REMOVAL
(1) Remove the spring from the vehicle.
(2) Position the spring eye in a press.
(3) Press the bushing out with an appropriate size
driver.
INSTALLATION
(1) Press new bushing into the spring eye with an
appropriate size driver. The bushing should be cen-
tered in the spring eye.
(2) Install the spring on the vehicle.
SHOCK
REMOVAL
(1) Raise vehicle and support axle.
(2) Remove the bolt and flag nut from the frame
crossmember bracket (Fig. 1).
(3) Remove the bolt and nut from the axle bracket.
(4) Remove the rear shock absorber from the vehi-
cle.
INSTALLATION
(1) Position the shock absorber in the brackets.
(2) Install the bolts through the brackets and the
shock. Install the flag nut on the top bolt and nut on
lower bolt.
(3) Tighten the upper and lower bolt/nuts Tighten
to 136 N.m (100 ft. lbs.)
(4) Remove the support and lower the vehicle.
SPRING
REMOVAL
(1) Raise the vehicle and support the axle to
remove all weight from the springs.
(2) Remove the nuts and spring clamp bolts that
attach the spring to the axle (Fig. 2) and (Fig. 3)and
(Fig. 4).
(3) Remove the nuts and bolts from the spring
front and rear shackle eyes.Note: To remove front
eye bolt on left side spring fuel tank must be
removed, (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL TANK - REMOVAL).
(4) Remove the spring from the vehicle.
(5) Remove the shackle from the spring.
Puller C-3894-A
Fig. 1 Shock Absorber
1 - FLAG NUT
2 - AXLE
3 - SHOCK
BR/BEREAR 2 - 27
REAR (Continued)

AXLE SHAFT SEALS
REMOVAL
(1) Remove hub bearings and axle shafts.
(2) Remove axle shaft seal from the differential
housing with a long drift or punch.Be careful not
to damage housing.
(3) Clean the inside perimeter of the differential
housing with fine crocus cloth.
INSTALLATION
(1) Apply a light film of oil to the inside lip of the
new axle shaft seal.
(2) Install the inner axle seal (Fig. 25).
(3) Install axles and hub bearings.
AXLE VACUUM MOTOR
DESCRIPTION
The disconnect axle control system consists of:
²Shift motor.
²Indicator switch.
²Vacuum switch.
²Vacuum harness (Fig. 26).
OPERATION
The shift motor receives a vacuum signal from the
switch mounted on the transfer case when the vehi-
cle operator wants to switch from two wheel drive
mode to four wheel drive mode, or vice versa. When
this signal is received, the shift motor begins to move
the shift fork and collar within the axle housing. In
the four wheel drive mode, the shift collar connects
the axle intermediate shaft to the axle shaft to sup-
ply engine power to both front wheels. In two wheel
drive mode, the shift collar is disengaged from the
intermediate shaft and the intermediate shaft is
allowed to free-spin. When the two shafts are disen-
gaged, the load on the engine is reduced, thereby pro-
viding better fuel economy and road handling.
Fig. 25 SEAL INSTALLATION
1 - DIFFERENTIAL HOUSING
2 - POSITION FOR OPEN-END WRENCH
3 - SPECIAL TOOL 5041-2
4 - SPECIAL TOOL 8417
5 - SEAL
6 - SPECIAL TOOL 8411
Fig. 26 VACUUM CONTROL SYSTEM
1 - CHECK VALVE
2 - CONTROL SWITCH ON TRANSFER CASE
3 - AIR VENT FILTER
4 - AXLE SHIFT MOTOR
5 - INDICATOR SWITCH
BR/BEFRONT AXLE - 248FBI 3 - 31

HYDRAULIC BOOSTER DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Slow Brake Pedal Return 1. Excessive seal friction in booster. 1. Replace booster.
2. Faulty spool valve action. 2. Replace booster.
3. Restriction in booster return hose. 3. Replace hose.
4. Damaged input rod. 4. Replace booster.
Excessive Brake Pedal
Effort.1. Internal or external seal leakage. 1. Replace booster.
2. Faulty steering pump. 2. Replace pump.
Brakes Self Apply 1. Dump valve faulty. 1. Replace booster.
2. Contamination in hydraulic
system.2. Flush hydraulic system and replace
booster.
3. Restriction in booster return hose. 3. Replace hose.
Booster Chatter, Pedal
Vibration1. Slipping pump belt. 1. Replace power steering belt.
2. Low pump fluid level. 2. Fill pump and check for leaks.
Grabbing Brakes 1. Low pump flow. 1. Test and repair/replace pump.
2. Faulty spool valve action. 2. Replace booster.
STANDARD PROCEDURE - BLEEDING
The hydraulic booster is generally self-bleeding,
this procedure will normally bleed the air from the
booster. Normal driving and operation of the unit will
remove any remaining trapped air.
(1) Fill power steering pump reservoir.
(2) Disconnect fuel shutdown relay and crank the
engine for several seconds, Refer to Fuel System for
relay location and WARNING.
(3) Check fluid level and add if necessary.
(4) Connect fuel shutdown relay and start the
engine.
(5) Turn the steering wheel slowly from lock to
lock twice.
(6) Stop the engine and discharge the accumulator
by depressing the brake pedal 5 times.
(7) Start the engine and turn the steering wheel
slowly from lock to lock twice.
(8) Turn off the engine and check fluid level and
add if necessary.
NOTE: If fluid foaming occurs, wait for foam to dis-
sipate and repeat steps 7 and 8.
REMOVAL
NOTE: If the booster is being replaced because the
power steering fluid is contaminated, flush the
power steering system before replacing the booster.(1) With engine off depress the brake pedal 5
times to discharge the accumulator.
(2) Remove brake lines from master cylinder.
(3) Remove mounting nuts from the master cylin-
der.
(4) Remove the bracket from the hydraulic booster
lines and master cylinder mounting studs.
(5) Remove the master cylinder.
(6) Remove the return hose and the two pressure
lines from the hydraulic booster (Fig. 28).
(7) Remove the booster push rod clip, washer and
rod remove from the brake pedal. (Fig. 29).
(8) Remove the mounting nuts from the hydraulic
booster and remove the booster (Fig. 30).
INSTALLATION
(1) Install the hydraulic booster and tighten the
mounting nuts to 28 N´m (21 ft. lbs.).
(2) Install the booster push rod, washer and clip
onto the brake pedal.
(3) Install the master cylinder on the mounting
studs. and tighten the mounting nuts to 23 N´m (17
ft. lbs.).
(4) Install the brake lines to the master cylinder
and tighten to 19-200 N´m (170-200 in. lbs.).
(5) Install the hydraulic booster line bracket onto
the master cylinder mounting studs.
(6) Install the master cylinder mounting nuts and
tighten to 23 N´m (17 ft. lbs.).
BR/BEBRAKES - BASE 5 - 19
POWER BRAKE BOOSTER (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
8. Incorrect coolant concentration 8. Check coolant. (Refer to
LUBRICATION & MAINTENANCE/
FLUID TYPES - DESCRIPTION).
9. Coolant not flowing through
system9. Check for coolant flow at radiator
filler neck with some coolant
removed, engine warm and
thermostat open. Coolant should be
observed flowing through radiator. If
flow is not observed, determine area
of obstruction and repair as
necessary.
10. Radiator or A/C condenser fins
are dirty or clogged.10. Remove insects and debris.
(Refer to 7 - COOLING -
STANDARD PROCEDURE).
11. Radiator core is corroded or
plugged.11. Have radiator re-cored or
replaced.
12. Aftermarket A/C installed
without proper radiator.12. Install proper radiator.
13. Fuel or ignition system
problems.13. Refer to 14 - Fuel System or 8 -
Electrical for diagnosis and testing
procedures.
14. Dragging brakes. 14. Check and correct as
necessary. (Refer to 5 - BRAKES -
DIAGNOSIS AND TESTING) for
correct procedures.
15. Bug screen or cardboard is
being used, reducing airflow.15. Remove bug screen or
cardboard.
16. Thermostat partially or
completely shut.16. Check thermostat operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT -
REMOVAL).
17. Viscous fan drive not operating
properly.17. Check fan drive operation and
replace as necessary. (Refer to 7 -
COOLING/ENGINE/FAN DRIVE
VISCOUS CLUTCH - REMOVAL).
18. Cylinder head gasket leaking. 18. Check for cylinder head gasket
leaks. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
19. Heater core leaking. 19. Check heater core for leaks.
(Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING).
Repair as necessary.
BR/BECOOLING 7 - 9
COOLING (Continued)

ENGINE COOLANT TEMP
SENSOR - 5.9L
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is
used to sense engine coolant temperature. The sensor
protrudes into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as engine coolant
temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM)
sends out a regulated 5 volt signal to the ECT sensor.
The PCM then monitors the signal as it passes
through the ECT sensor to the sensor ground (sensor
return).
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the
following calculations:
²for engine coolant temperature gauge operation
through CCD or PCI (J1850) communications
²Injector pulse-width
²Spark-advance curves
²ASD relay shut-down times
²Idle Air Control (IAC) motor key-on steps
²Pulse-width prime-shot during cranking
²O2 sensor closed loop times
²Purge solenoid on/off times
²EGR solenoid on/off times (if equipped)
²Leak Detection Pump operation (if equipped)
²Radiator fan relay on/off times (if equipped)²Target idle speed
REMOVAL
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING. COOLING SYSTEM
MUST BE PARTIALLY DRAINED BEFORE REMOV-
ING THE COOLANT TEMPERATURE SENSOR.
REFER TO GROUP 7, COOLING.
(1) Partially drain cooling system (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(2) Remove air cleaner assembly.
(3) Disconnect electrical connector from sensor
(Fig. 14).
(4)Engines with air conditioning:When
removing the connector from sensor, do not pull
directly on wiring harness. Fabricate an L-shaped
hook tool from a coat hanger (approximately eight
inches long). Place the hook part of tool under the
connector for removal. The connector is snapped onto
the sensor. It is not equipped with a lock type tab.
(5) Remove sensor from intake manifold.
INSTALLATION
(1) Install sensor.
(2) Tighten to 6±8 N´m (55±75 in. lbs.) torque.
(3) Connect electrical connector to sensor. The sen-
sor connector is symmetrical (not indexed). It can be
installed to the sensor in either direction.
(4) Install air cleaner assembly.
(5) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Fig. 13 Block HeaterÐDiesel Engine
1 - BLOCK HEATER
Fig. 14 Engine Coolant Temperature
1 - GENERATOR
2 - A/C COMPRESSOR
3 - ENGINE COOLANT TEMPERATURE SENSOR
4 - ELEC. CONN.
BR/BEENGINE 7 - 47
ENGINE BLOCK HEATER - 5.9L DIESEL (Continued)

RADIO NOISE SUPPRESSION
COMPONENTS
DESCRIPTION
Radio Frequency Interference (RFI) and Electro-
Magnetic Interference (EMI) noise suppression is
accomplished primarily through circuitry internal to
the radio receivers. These internal suppression
devices are only serviced as part of the radio receiver.
External suppression devices that are used on this
vehicle to control RFI or EMI noise include the fol-
lowing:
²Radio antenna base ground
²Radio receiver chassis ground wire or strap
²Engine-to-body ground straps
²Cab-to-bed ground strap
²Heater core ground strap
²Resistor-type spark plugs
²Radio suppression-type secondary ignition wir-
ing.
For more information on the spark plugs and sec-
ondary ignition components, refer to Electrical, Igni-
tion Control.
DIAGNOSIS AND TESTING - RADIO NOISE
SUPPRESSION COMPONENTS
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds. Inspect the ground paths
and connections at the following locations:
²Blower motor
²Cab-to-bed ground strap
²Electric fuel pump
²Engine-to-body ground straps
²Generator
²Ignition module
²Heater core ground strap
²Radio antenna base ground
²Radio receiver chassis ground wire or strap
²Wiper motor.If the source of RFI or EMI noise is identified as a
component on the vehicle (i.e., generator, blower
motor, etc.), the ground path for that component
should be checked. If excessive resistance is found in
any ground circuit, clean, tighten, or repair the
ground circuits or connections to ground as required
before considering any component replacement.
For service and inspection of secondary ignition
components, refer to Electrical, Ignition Control.
Inspect the following secondary ignition system com-
ponents:
²Distributor cap and rotor
²Ignition coil
²Spark plugs
²Spark plug wire routing and condition.
Reroute the spark plug wires or replace the faulty
components as required.
If the source of the RFI or EMI noise is identified
as two-way mobile radio or telephone equipment,
check the equipment installation for the following:
²Power connections should be made directly to
the battery, and fused as closely to the battery as
possible.
²The antenna should be mounted on the roof or
toward the rear of the vehicle. Remember that mag-
netic antenna mounts on the roof panel can adversely
affect the operation of an overhead console compass,
if the vehicle is so equipped.
²The antenna cable should be fully shielded coax-
ial cable, should be as short as is practical, and
should be routed away from the factory-installed
vehicle wire harnesses whenever possible.
²The antenna and cable must be carefully
matched to ensure a low Standing Wave Ratio
(SWR).
Fleet vehicles are available with an extra-cost RFI-
suppressed Powertrain Control Module (PCM). This
unit reduces interference generated by the PCM on
some radio frequencies used in two-way radio com-
munications. However, this unit will not resolve com-
plaints of RFI in the commercial AM or FM radio
frequency ranges.
ENGINE-TO-BODY GROUND
STRAP
REMOVAL
(1) Remove the screw that secures the engine-to-
body ground strap eyelet to the dash panel (Fig. 10).
(2) Remove the screw that secures the engine-to-
body ground strap eyelet to the back of the engine
cylinder head (Fig. 11) or (Fig. 12).
8A - 12 AUDIOBR/BE