change wheel ISUZU TROOPER 1995 Workshop Manual

•:1
SECTION TABLE OF CONTENTS
. GENERAL INFORMATION OA General Information OB Maintenance and Lubrication
WORKSHOP MANUAL
HEATING AND AIR CONDITIONING 1A Heating and Ventilation
1B Air Conditioning 1D Compressor Overhaul
TROOPER
FRAME, BUMPERS AND SHEET METAL
2A Frame 2B Bumpers
(UX) 2C Sheet Metal
STEERING, SUSPENSION, WHEELS AND TIRES
3 Diagnosis 3A Front End Alignment 3B1 Power Steering Gear and Pump 3B3 Steering Linkage 3C Front Suspension 3D Rear Suspension 3E Wheels and Tires 3F4 Supplemental Restraint System Steering Wheel
FOREWORD and Column
PROPELLER SHAFT AND AXLE 4A Propeller Shaft This manual includes special notes, important points, service 4B Rear Axle
data, precautions, etc. that are needed for the maintenance, 4C Front Driving Axle
adjustments, service, removal and installation of vehicle BRAKES components. 5A Hydraulic Brakes
·~ m rmation, illustrations and specifications contained in 5A1 Brake Booster System
.. _,. 5A2 Disc Brakes ~ this ma. ~-based D.fl the latest product information 5A3 Rear Wheei_Antilock Brake System (RWAL)
available at the tirrHHrl·publication. 5A4 4-wheel Antilock Brake System (ABS)
5C Parking Brakes All rights are reserved to make changes at any time without ENGINE notice. 6· Engine General Information Arrangement of the material is shown in the table of contents &A General Engine Mechanical
on the right-hand side of this page. A black spot on the first 6A1 3.2L VB Engine
page of each section can be seen on the edge of the book &B Engine Cooling
6C Engine Fuel below each section title. These point to a more detailed table &D Engine Electrical of contents preceding each section. 6D1 Battery 6D2 Cranking System
This manual applies to 1995 models. 6D3 Charging System 6D4-Ignition System 6E2. Driveability and Emissions 6F Engine Exhaust
TRANSMISSION 7A-Automatic Transmission (4L30·E) 7B Manual Transmission 7C Clutch 7D Transfer Case
8 CHASSIS ELECTRICAL
ACCESSORIES 9A Radio 9B Cruise Control 9J Supplemental Restraint System (SRS)-AIR BAG
10 BODY
APPENDIX A CONVERSION TABLES PUBLICATION NO. UXOO-WSM-L0001-00
APPENDIXB HYDRAULIC CIRCUIT DIAGRAM (Automatic Transmission)
© 1994 ISUZU MOTORS LIMITED

MILEAGE
ONL
V
ITEMS MILEAGE
ONLY
ITEMS
7.5
1
CHANGE
FRONT
AND
REAR AXLE
OIL
2
CHANGE
MANUAL
TRANSMISSION
AND
TRANSFER CASE
OIL
3
REPLACE AIR
CLEANER FILTER
4
REPLACE SPARK PLUGS
5
CHANGE ENGINE
COOLANT
6
*REPLACE
TIMING
BELT
7
ROT
ATE
TIRES
8
CHANGE
POWER STEERING FLUID
9
REPACK FRONT
WHEEL
BEARINGS
10
REPACK FRONT
FREE-WHEELING HUBS
11
CLEAN
RADIATOR
CORE
AND
AIR CONDITIONING CONDENSER
12
INSPECT SPARK PLUG WIRE
'
-----
* : Replacement
of the
timing
belt
is recommended
at every
60,000
miles
(96,000
km).
Failure
to replace
the timing
belt
may
result
in damage to the engine.
)
•
IN THOUSANDS
OF
MILES
(USE
ODOMETER
READING)
15 22.5
30
37.5 45 52.5
60
67.5
75
82.5
90
97.5
'
-
'---
~--·-L....
SHADED AREA
INDICATES SERVICE TO
BE
PERFORMED.
)
105
112.5
120 '-------
(x 1000
miles)
DESCRIPTION ------
)
0 ~ s: l> ~ z l> z 0 m l> z c r­c m :a c; ~ 0 2

(
(
(
MILEAGE/MONTHS
rn
I ffi
IN THOUSANDS
OF
MILES
(USE
ODOMETER READING)
(x 1000
miles)
~ +~
7.5 15 22.5
30
37.5 45 52.5
60
67.5
75
82.5
90
97.5
105
112.5
120 DESCRIPTION
1
CHECK
BATTERY
FLUID
LEVEL
12
2'-'.:j:
:':
';;;;;
I '' ''
,,,,,,,,,:
[}
2
CHECK
ENGINE
COOLANT
LEVEL
12
':iti:·:
(''''/''?
'';?
,,,,,,,;.;.,.,....
,,,~~
3
CHECK
BRAKE
AND
CLUTCH
FLUID
LEVEL
12
:;:;:;:;:·:·:·.
\::':\' '\"':(\':'''''''''
:'·'·'·:·.,.,,,,
d~~~~~~-------------~
)''
'"''''{''''
'}';;o;o;;
l':':':·:o·.·o·····
4
CHECK
FLUID
LEAKS
12
•.•••..••• ,,......
,,,,,,,,,,,
5
* CHANGE
ENGINE
OIL
12
:.•••:•····
f ) : •
: ; ' {
1:':''''
6
*REPLACE
ENGINE
OIL
FILTER
12
{\::::::::;
[:(o:'.
7
CHECK
COOLING
AND
HEATER
HOSES
12
I : ' :
?
,,,.,,,,,.,:,
.. ;
! • !
•••••••••.
8
CHECK
EXHAUST
SYSTEM
12
I
~
J
:
: ••;·,·····,:·:';';·
•••::::::::::·:;.;
I ;J
., ..... .
9
CHECK
FUEL
LINE
AND
FUEL
TANK/CAP
12
10
CHECK
ENGINE
DRIVE
BELTS
24
. .
I
I
11
CHECKTIRESANDWHEELS
12
li
1:;:~:
}::,
..... ::::, .. ,::,:,:,:,·····
j
12
CHECK
STEERING
OPERATION
12
1
r ., .. ,,.,,.
·
I
13
CHECK
BRAKE
LINES
AND
HOSE
12
~
~
<
.,>
/ ':'??i'
}
J
t
''}{
14
CHECK
DISC
BRAKES
12
10
}}
UL
'I I
•....
15
CHECK
BRAKE
PEDAL
PLAY
12
I"
.. )t
16
CHECK
PARKING
BRAKE
12
li
I
17
LUBE
ACCELERATOR
LINKAGE
6
,,.:
....
I
18
CHECK
SUSPENSION
AND
STEERING
12
••·•••·•··•
19
LUBE
BODY
AND
CHASSIS
6
1''''':'''''''''''
20
LUBE
FRONT
AND
REAR
PROPELLER
SHAFT 6
{:
!: • :•••••l
21
CHECK
PROPELLER
SHAFT FLANGE
TORQUE
12
•
22
*CHECK AUTOMATIC TRANSMISSION
FLUID
12
... ,, ,....
@{I{
,,,,,,,,
ttJ
·~+---------------!
23
CHECK
AUTO
CRUISE
CONTROL
LINKAGE
AND
HOSES
12
~ .
:l
!•••:
24
CHECK
CLUTCH
LINES
AND
HOSE
12
25
LUBE
CLUTCH
PEDAL
SPRING,
BUSHING
AND
CLEVIS
PIN
6
l':":"·:"ii
26
CHECK
CLUTCH
PEDAL
FREE
PLAY
12
1/JJ(
21
cHEcK sTARTER SAFETY swiTCH 12
1/,,,,.,,,,,,,,,
,,,,,,,,,
-~~~--~~~~~~-~~~~~[============J
28
CHECK
ACCELERATOR
LINKAGE
12
m ::::::::]
!•'····
'.!
Under
severe driving conditions,
additional
maintenance
is required.
Refer to
"Severe
driving
conditions".
SHADED AREA
INDICATES
SERVICE
TO
BE PERFORMED.
s: ~ 2 -1 m 2 )> 2 n m )> 2 c r­c m ::u n ~ 0 2 Q ~

FLUID LEVEL CHECK
A fluid loss in any system (except windshield
washer) may indicate a problem. Repair the system
at once.
Engine
oil level -Check level and add if
necessary. The best time to check the engine oil
level is
when the oil is warm. After stopping the
engine with the vehicle on a level surface, wait a
few minutes for the oil to drain back to the oil pan.
Pull
out the oil level indicator (dipstick). Wipe it
clean and push the oil level indicator back down all
the
way. Pull out the oil level indicator, keeping the
tip down, and look at the oil level on it.
Add oil, if needed, to keep the oil level above
the
"ADD" mark and between the "ADD" and
"FULL" marks in the operating range area. Avoid
overfilling the engine since this may cause engine
damage. Push
the oil level indicator back down all
the
way after taking the reading.
If you check the oil level when the oil is cold, do
not run the engine first. The cold oil will not drain
back
to the pan fast enough to give a true oil level.
Engine coolant level and condition -Check
engine coolant level in the coolant reservoir and
add engine
coolant if necessary. Inspect the engine
coolant and replace it if dirty or rusty.
Windshield washer fluid level -Check washer
fluid level in reservoir and add if necessary.
Power steering system reservoir level-Check
and keep at
proper level.
Brake master cylinder reservoir level -Check
fluid. Keep fluid at proper level. A low fluid level
can indicate
worn disc brake pads which may need
to be serviced.
Hydraulic clutch system -Check fluid l~vel in
the reservoir.
Add fluid as required.
Battery fluid level -Check fluid level in the
battery.
FLUID LEAK CHECK
Check for fuel, water, oil or other fluid leaks by
looking at the surface beneath the vehicle after it
has been parked for a while. Water dripping from
the air conditioning system after use is normal. If
you notice gasoline fumes or fluid at any time,
locate the source and correct it at once.
ENGINE OIL AND OIL FILTER
REPLACEMENT
Always use API SE, SF, SG, SH or ILSAC GF-1
quality oils of the proper viscosity.
When choosing an oil, consider the range of
temperatures the car will be operated in before the
next oil change. Then, select the recommended oil
viscosity
from the chart (Fig. OB-1).
Always change the oil and the oil filter as soon as
possible after driving in a dust storm.
MAINTENANCE AND LUBRICATION OB-5
ENGINE COOLING SYSTEM INSPECTION
Inspect coolant/anti-freeze. If coolant is dirty or
rusty, drain, flush and refill with new coolant. Keep
coolant at the proper mixture for proper freeze
protection,
corrosion inhibitor level and best engine
operating temperature.
Inspect hoses and replace if
cracked, swollen or deteriorated. Tighten hose
clamps if equipped with screw-type clamps. Clean
outside of radiator and air conditioning condenser.
Wash
filler cap and neck. To help ensure proper
operation, a pressure test of both the cooling
system and cap is also recommended.
EXHAUST SYSTEM INSPECTION
Visually inspect the exhaust pipes, muffler, heat
shields and hangers
for cracks, deterioration, or
damage.
Be alert to any changes in the sound of the exhaust
system
or any smell of fumes. These are signs the
system may be leaking or overheating. Repair the
system at once,
if these conditions exist. (See also
"Engine Exhaust Gas Safety" and "Three Way
Catalytic Converter" in Owner's manual.)
FUEL CAP, FUEL LINES, AND FUEL TANK
INSPECTION
Inspect the fuel tank, the fuel cap and the fuel lines
every
60,000 miles (96,000 km) for damage which
could cause leakage.
Inspect the fuel cap and the gasket for correct sealing
and physical damage. Replace any damaged parts.
DRIVE BELT INSPECTION
Check the belts driving the steering oil pump, the air
conditioning compressor, and the generator
for
cracks, fraying, wear, and correct tension every 30,000
miles (48,000 km). Adjust or replace as necessary.
WHEEL ALIGNMENT, BALANCE AND
TIRES OPERATION
Uneven or abnormal tire wear, or a pull right or left
on a straight and level road may show the need for
a wheel alignment. A vibration of the steering
wheel or seat at normal highway speeds means a
wheel balancing is needed. Check tire pressure
when the tires are "cold" (include the spare).
Maintain pressure as shown in the tire placard,
which is located on the driver's door lock pillar.
STEERING SYSTEM OPERATION
Be alert for any changes in steering action. An
inspection
or service is needed when the steering
wheel is harder
to turn or has too much free play, or
if there are unusual sounds when turning or parking.

OB-6 MAINTENANCE AND LUBRICATION
BRAKE SYSTEMS OPERATION
Watch for the "BRAKE" light coming on. Other
signs of possible brake trouble are such things as
repeated pulling to one side when braking, unusual
sounds
when braking or between brake
applications,
or increased brake pedal travel. If you
note one of these conditions, repair the system at
once.
For convenience, the
following should be done
when wheels are removed for rotation: Inspect lines
and hoses
for proper hookup, bindings, leaks, crack,
chafing etc.
Inspect disc brake pads for wear and
rotors
for surface condition.
Inspect other brake parts, including parking brake
drums, linings etc., at the same time. Check parking
brake adjustment.
Inspect brakes more often if habit or
conditions
result in frequent braking.
PARKING BRAKE AND TRANSMISSION
PARK MECHANISM OPERATION
Park on a fairly steep hill and hold the vehicle with
the parking brake only. This checks holding ability.
On
automatic transmission vehicles, shifting from
"P" position to the other positions cannot be made
unless
the brake pedal is depressed when the key
switch is in
"ON" position or the engine running.
WARNING
•
Before checking starter safety switch
operation below,
be sure to have enough
room around the
vehicle. Then firmly apply
both the parking brake and the regular brake.
Do not
use the accelerator pedal. If the engine
starts, be ready
to turn off the key promptly.
Take these precautions because the vehicle
could move
without warning and possibly
cause personal injury
or property damage.
STARTER SAFETY SWITCH OPERATION
(AUTOMATIC TRANSMISSION)
Check by trying to start the engine in each gear
while setting the parking brake and the foot brake.
The starter
should crank only in "P" (Park) or "N"
(Neutral).
STARTER SAFETY SWITCH OPERATION
(MANUAL TRANSMISSION)
To check, place the shift lever in "Neutral", push
the clutch pedal halfway and try to start. The starter
should not crank. The starter should crank only
when the clutch pedal is fully depressed.
ACCELERATOR LINKAGE LUBRICATION
Lubricate the accelerator pedal fulcrum pin with
chassis grease.
STEERING AND SUSPENSION
INSPECTION
Inspect front and rear suspension and steering
system
for damaged, loose or missing parts or signs
of wear. Inspect power steering lines and hoses for
proper hookup, binding, leaks, cracks, chafing, etc.
BODY AND CHASSIS LUBRICATION
Lubricate the key lock cylinders, the hood latch, the
hood and door hinges, the door check link, the
parking cable guides,
the underbody contact points,
and the linkage.
PROPELLER SHAFT INSPECTION AND
LUBRICATION
Lubricate sliding yoke and universal joints with
grease containing MOS2 (disulfide molybdenum
type grease) at the interval shown in the
Maintenance Schedule. Check for play in normal
direction of rotation of sliding yoke and universal
joints. Also check
propeller shaft flange-to-pinion
bolts for proper torque of 63 N·m (46 lb·ft) for front
and rear propeller shaft.
AUTOMATIC TRANSMISSION FLUID
INSPECTION
Check the lubricant level every 7,500 miles (12,000
km) and add lubricant
if necessary.
Under harsh operating conditions, such as constant
driving in heavy city traffic during
hot weather, or in
hilly or mountainous terrain, change the transmission
fluid and service the
sump filter after every 20,000
miles (32,000 km) of operation.
AUTO CRUISE CONTROL INSPECTION
Check to see if the clearance between cruise link and
accelerator is normal. Also check that the vacuum
hoses are routed and connected properly.
CLUTCH LINES AND HOSES INSPECTION
Check lines and hoses for proper attachment,
binding, leaks, cracks, chafing, deterioration, etc.
Any questionable parts should be replaced or
repaired at once. When abrasion or wear is evident
on lines or hoses, the cause must be corrected.
..

FRONT END ALIGNMENT 3A-3
ON-VEHICLE SERVICE
INSPECTION
Before making any adjustments affecting caster,
camber or toe-in, the following front end inspection
should be made.
I L•IINSPECT
1. Tires for proper inflation pressure. Refer to
"Wheels and Tires" in section 3E.
2. Front wheel bearings for proper adjustment.
Refer to "Front Wheel Drive" in section 4C.
3. Ball joints, tie rod ends and relay rods. If
excessive looseness is noted, correct before
adjusting. Refer
to "Steering Linkage" in section
3B3.
4. Wheel and tires for run-out. Refer to "Wheels
and Tires" in section 3E.
5. Trim height. If not within specifications, the
correction
must be made before adjusting caster.
6. Steering gear for looseness at the frame.
7. Shock absorbers for leaks or any noticeable
noise.
Refer
to "Front Suspension" in section 3C.
8. Control arms or stabilizer bar attachment for
looseness. Refer to "Front Suspension" in section
3C.
9. Alignment equipment. Follow the manufacturer's
instructions.
10. Level of the vehicle. The vehicle must be on a
level surface.
TRIM HEIGHT ADJUSTMENT
Adjust the trim height by means of the adjusting bolt
on the height control arms (Fig. 3A-4 and 5).
W CAUTION:
When adjusting front end alignment, be sure to
begin with trim height as trim height adjustment
may change other adjusted alignments.
1. Check and adjust the tire inflation pressures.
2. Park the vehicle on a level ground and move the
front of the vehicle up and down several times to
settle the suspension.
3. Make necessary adjustment with the adjusting
bolt on the height control arms.
WHEEL
ALIGNMENT SPECIFICATION
Trim height (Z) 129 mm (5.08 in)
Lower
ball joint
B
Fig. 3A-4
Fig. 3A-5
CASTER ADJUSTMENT
Level ground
The caster angle can be adjusted by means of the
caster shims installed between the chassis frame and
fulcrum pins (Fig. 3A-6 and 7).
WHEEL
ALIGNMENT SPECIFICATION
LWB
Caster angle
SWB
W CAUTION:
Left and right side to be equal within 30'
NOTE:
Difference of the caster shim front/rear thickness shall
be 3.6
mm (0.142 in) or less. Overall thickness of caster
shim and camber shim shall be 10.8 mm (0.425 in) or
less.

3A-4 FRONT END ALIGNMENT
• Tighten the fulcrum pin bolt to the specified torque.
1~1 Torque N·m (lb·ft) 152 (112)
Fig. 3A-6
0 t Front
0
Fig. 3A-8
Fig. 3A-9
\fl CAUTION:
t Front
'(/ Left and right side to be equal within 30'
NOTE:
Fig. 3A-7
CAMBER ADJUSTMENT
Overall thickness of caster shim and camber shim shall
be 10.8 mm (0.425 in) or less.
The camber angle can be adjusted by means of the
camber shims
installed in position between the chassis
frame and
fulcrum pins (Fig. 3A-8 and 9).
• Tighten the fulcrum pin bolt to the specified torque.
~~~ Torque N·m (lb·ft) 152 (112)
WHEEL ALIGNMENT SPECIFICATION
Camber angle o· ± 30'
King pin inclination 12° 30' ± 30'
Position of shims
Front side Rear
side Camber angle Caster angle
1---When
added When
removed Decreases Decreases
When removed When
added
Increases Increases Caster shim
When removed Unchanged Decreases
When added Unchanged
Increases
When added Decreases
Unchanged
Camber shim
When removed
Increases Unchanged

FRONT SUSPENSION 3C-1
SECTION 3C
FRONT SUSPENSION
'\f CAUTION:
When fasteners are removed, always reinstall them at the same location from which they were removed.
If a fastener needs to be replaced, use the correct part number fastener for that application. If the correct
part
number fastener is not available, a fastener of equal size and strength (or stronger) may be used.
Fasteners
that are not reused, and those requiring thread locking compound, will be called out. The correct
torque value must be used when installing fasteners that require it. If the above conditions are not
followed, parts or system damage could result.
Refer to section 3A in this manual for the wheel alignment procedure.
CONTENTS
General Description .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 3C- 1
On-Vehicle Service .............................. 3C-3
Shock Absorber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3C-3
Stabilizer Bar . .. .. . .. .. ..

.. . .. .. . .. .. .. . .. .. .. . 3C- 4
Torsion Bar
.................................... 3C-5
Knuckle . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3C-7
Upper
Control Arm ........................... 3C-10
Lower Control Arm ........................... 3C-13
Upper Ball Joint ............................... 3C- 16
Lower
Ball Joint ............................... 3C-18
Main Data and Specifications.................. 3C-20
General
Specifications . .

. . . . . . . . . . . . . . . . . . . . . 3C-
20
Torque Specifications ........................ 3C-21
Special Tools ..................................... 3C-22
GENERAL DESCRIPTION
The front suspension is designed to allow each wheel
to compensate for changes in the road surface level
without greatly affecting the opposite wheel. Each
wheel is independently connected to the frame by a
steering
knuckle, ball joint assemblies, and upper and
lower control arms. The front wheels are held in
proper relationship to each other by two outer track
rods
which are connected to steering arms on the
knuckles and to a center track rod.
All models have a front suspension system consisting
of control arms, stabilizer bar, shock absorber and a
torsion bar. The front end of the torsion bar is
attached
to the lower control arm. The rear of the
torsion bar is mounted into a height control arm at the
crossmember. Vehicle trim height is controlled by
adjusting this arm.
Shock absorbers are
mounted between the brackets
on the
frame and the lower control arms. The lower
portion of each shock absorber is attached to the
lower control arm by a bolt and nut. The upper portion
of each shock absorber extends through a frame
bracket and is secured with two rubber bushings,
three retainers and a nut.
Ball joint assemblies are bolted to the outer end of the
upper and lower control arm and are attached to the
steering
knuckle by nuts and cotter pins.
The
inner ends of the upper control arm have pressed
in bushings.
Bolts, passing through the bushing,
attach the control arm to the frame. The inner ends of
the lower control arm are attached to the frame by
bolts passing through the bushings, which are
pressed in the frame.
Side
roll of the front suspension is controlled by a
spring steel stabilizer bar. It is mounted in rubber
bushings, which are held to the crossmember by
brackets. The ends of the stabilizer bar are connected
to the lower control arms by links.

WHEELS AND TIRES 3E-1
TIRES
REPLACEMENT
UNIT REPAIR
WHEELS
REPLACEMENT
When replacement is necessary, the original metric
the size should be used. Most metric tire sizes do not
have exact corresponding alphanumeric tire sizes. It
is recommended that new tires be installed in pairs on
the same axle. If necessary to replace only one tire, it
should be paired with tire having the most tread, to
equalize braking traction.
w CAUTION:
Do not mix different types of tires such as radial,
bias and bias-belted tires except in emergencies,
because
vehicle handling may be seriously
affected and may result in loss of control.
TIRE DISMOUNTING
Remove valve cap on valve step and deflate the tire.
Then use a
tire changing machine to mount or
dismount tires.
Follow the equipment manufacturer's instruction. Do
not use hand tools or tire lever alone to change tires
as they may damage the tire beads or wheel rim.
TIRE MOUNTING
Rim bead seats should be cleaned with a wire brush
....._., or coarse steel wool to remove lubricants, and light
rust. Before mounting a tire, the bead area should be
well lubricated with an approved tire lubricant.
After mounting, inflate the tire to 196kPa (28 psi) so
that beads are completely seated. Inflate the air to
specified pressure and install valve cap to the stem.
\f WARNING:
Never stand over tire when inflating. Bead may
break when bead snaps over rim's safety hump
and cause serious personal injury.
Never exceed
240 kPa (35 psi) pressure when
inflating. If 240 kPa (35 psi) pressure will not
seat beads, deflate, re-lubricate and re-inflate.
Over
inflation may cause the bead to break and
cause serious
personal injury.
TIRE REPAIR
There are many different materials on the market
used to repair tires.
Manufacturers have published detailed instructions
on how and when to repair tires. These instructions
can be obtained from the tire manufacturer if they are
not included with the repair kit. Damaged
wheels and wheels with excessive run-out
must be replaced.
Fig. 3E-10
Wheel
run-out at rim
Steel Aluminum
@ Vertical play: 1.5 (0.059) 0.7
(0.028) Less than mm(in)
@ Horizontal play: 1.5 (0.059) 0.7
(0.028) Less than mm(in)

REAR AXLE 48-3
DIAGNOSIS OF REAR AXLE NOISE
Many noises that seem to come from the rear axle
actually
originate from other sources such as tires,
road surface, wheel bearings, engine, transmission,
muffler,
or body drumming. Investigate to find the
source
ofthe noise before disassembling the rear axle.
Rear axles,
like any other mechanical device, are not
absolutely quiet but should be considered quiet unless
some abnormal noise is present.
To make a systematic check
for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct
level, and then drive the vehicle far enough to
thoroughly warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run
the engine speed
slowly up and down to
determine if the noise is caused by exhaust,
muffler noise, or other engine conditions.
4. Tire noise changes with different road surfaces;
axle noises do not. Temporarily inflate all tires to
344
kPa (50 psi) (for test purposes only). This will
change noise caused by tires but will not affect
noise caused by the rear
axle.
Rear axle nose usually stops when coasting at
speeds under
48 km/h (30 mph); however, tire
noise continues
with a lower tone. Rear axle noise
usually changes when comparing pull and coast,
but tire noise stays about the same.
Distinguish between tire noise and rear
axle noise
by noting
if the noise changes with various
speeds
or sudden acceleration and deceleration.
Exhaust and
axle noise vary under these
conditions,
while tire noise remains constant and
is more pronounced at speeds
of 32 to 48 km/h
(20 to 30 mph). Further check for tire noise by
driving the vehicle
over smooth pavements or dirt
roads (not gravel) with the tires at normal
pressure.
If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause
noise
which may be confused with rear axle
noise; however, front wheel bearing noise does
not change when comparing drive and coast.
Light application
of the brake while holding
vehicle speed steady
will often cause wheel
bearing noise to diminish. Front wheel bearings
may be checked for noise by jacking up the
wheels and spinning them
or by shaking the
wheels
to determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen
out rear axle noise when
correctly installed. Check to see that there is no
link or rod loosened or metal-to-metal contact.
7. Make sure that there is no metal-to-metal contact
between the
floor and the frame.
After the noise has been determined to be in the axle,
the type of axle noise should be determined, in order to
make any necessary repairs.
GEAR NOISE
Gear noise (whine) is audible from 32 to 89 km/h (20 to
55 mph) under four driving conditions.
1. In drive under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle
from driving the engine while the vehicle slows
down gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the
throttle closed. The gear noise is
usually more
noticeable between 48 and 64
km/h (30 and 40
mph) and 80 and 89 km/h (50 and 55 mph).
BEARING NOISE
Bad bearings generally produce a rough growl or
grating sound, rather than the whine typical of gear
noise. Bearing noise frequently
"wow-wows" at
bearing rpm, indicating a bad pinion
or rear axle side
bearing. This noise can
be confused with rear wheel
bearing noise.
REAR WHEEL BEARING NOISE
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in the neutral.
Noise may diminish by gentle braking. Jack up the rear
wheels, spin them by hand and
listen for noise at the
hubs. Replace any faulty
wheel bearings.
KNOCK AT LOW SPEEDS
Low speed knock can be caused by worn universal
joints or a side gear hub counter bore in the cage that is
worn oversize. Inspect and replace universal joints or
cage and side gears as required.
BACKLASH CLUNK
Excessive clunk on acceleration and deceleration can
be caused by a worn rear axle pinion shaft, a worn
cage, excessive clearance between the axle and the
side gear splines, excessive clearance between the
side gear hub and the counterbore in the cage,
worn
pinion and side gear teeth, worn thrust washers, or
excessive drive pinion and ring gear backlash.
Remove
worn parts and replace as required. Select
close-fitting parts when possible. Adjust pinion and
ring gear backlash.