The front axle consists of the front hubs, knuckles,
drive shaft, wheel bearings, ball joints, front differen-
tial, and free wheeling clutch. The features are:

• The structural method of press fitting unit bearing

into front hub is applied.

• The wheel bearing uses a taper roller unit bear-

ing. A rotor for detecting the wheel speed is
press-fitted to the UJ outer wheel.
NOTE: DOJ: Double Offset Joint. UJ: Under cut
Joint.

• Drive shafts incorporate UJ-DOJ-type constant

velocity ball joint has high power transmission
efficiency and reduces vibration and noise.

• A vacuum-type free wheeling clutch has been

adopted in the freewheel mechanism. Its solenoid
valve and actuator Switch powertrain between
RWD and 4WD.

• The differential support method is a four-point

elastic support method which reduce vibration
and noise.

FRONT AXLE DIAGNOSIS

INTRODUCTION TO FRONT AXLE DIAGNOSIS

M1261005500210

The 4WD vehicle incorporates a free wheeling clutch
as the free-wheeling mechanism. The free wheeling
clutch is configured of the mainshaft, shift fork and
clutch gears, etc., and is electrically controlled.

If the clutch does not lock or locks but does not
become free, there may be electrical trouble or the
component may be faulty. Noise from the driveshaft,
inner shaft or differential can be caused by a compo-
nent defect.

FRONT AXLE DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1261005600110

Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will be sure that you
have exhausted most of the possible ways to find a
front axle fault.
1. Gather information from the customer.

2. Verify that the condition described by the

customer exists.

3. Find the malfunction by following the Symptom

Chart.

4. Verify malfunction is eliminated.

SYMPTOM CHART

M1261005700270

SYMPTOMS

INSPECTION
PROCEDURE

REFERENCE PAGE

Free wheeling
Clutch

Does not lock

P.26-3

Locks but does not become free

P.26-3

Driveshaft,
inner shaft

Noise during wheel rotation

P.26-4

Noise due to excessive wheel play in
turning direction

P.26-4

Differential

Constant noise

P.26-4

Gear noise while driving

P.26-6

Gear noise while coasting

P.26-7

Bearing noise while driving or coasting

Noise while turning

Heat

Oil leakage

FRONT AXLE DIAGNOSIS

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FRONT AXLE

26-3

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1:Does not Lock

DIAGNOSIS

STEP 1. Check for looseness in the actuator
assembly installation bolt.

Q: Is the actuator assembly installation bolt

loosened?

YES :

Tighten to 17

± 3 N⋅m (13 ± 2 ft-lb). Then go

to Step 7.

NO :

Go to Step 2.

STEP 2. Check the vacuum tank for damage.

Q: Is the vacuum tank damaged?

YES :

Replace the tank. Then go to Step 7.

NO :

Go to Step 3.

STEP 3. Check the check valve for damage.

Q: Is the check valve damaged?

YES :

Replace the valve. Then go to Step 7.

NO :

Go to Step 4.

STEP 4. Check the actuator assembly for
damage.

Q: Is the actuator assembly damaged?

YES :

Replace the actuator assembly. Then go to

Step 7.

NO :

Go to Step 5.

STEP 5. Check the solenoid valve operation.

Refer to

P.26-16

Q: Is the solenoid valve operation in good condition?

YES :

Go to Step 6.

NO :

Replace the valve. Then go to Step 7.

STEP 6. Check the shift fork, mainshaft and
clutch gear for damage.

Q: Is the shift fork, mainshaft or clutch gear

damaged?

YES :

Replace the damaged part. Then go to Step

NO :

Go to Step 7.

STEP 7. Retest the system.

Q: Does clutch locks?

YES :

The procedure is complete.

NO :

Repeat from Step 1.

INSPECTION PROCEDURE 2:Locks but does not Become Free

DIAGNOSIS

STEP 1. Check whether foreign material has
entered the mainshaft and clutch gear or clutch
sleeve and clutch gear teeth.

Q: Has foreign material entered the mainshaft and

clutch gear or clutch sleeve and clutch gear teeth?

YES :

Clean the teeth or replace the part. Then go

to Step 2.

NO :

There is no action to be taken.

STEP 2. Retest the system.

Q: Does clutch become free?

YES :

The procedure is complete.

NO :

Repeat from Step 1.

FRONT AXLE DIAGNOSIS

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FRONT AXLE

26-4

INSPECTION PROCEDURE 3:Noise during Wheel Rotation

DIAGNOSIS

STEP 1. Check the housing tube and inner shaft
for bending.

Q: Is the housing tube and inner shaft bent?

YES :

Replace the part. Then go to Step 4.

NO :

Go to step 2.

STEP 2. Check the inner shaft bearing for wear.

Q: Is the inner shaft bearing worn?

YES :

Replace the bearings. Then go to Step 4.

NO :

Go to Step 3.

STEP 3. Check the driveshaft assembly for wear,
damage or bending.

Q: Is the driveshaft assembly worn, damaged or bent?

YES :

Replace the driveshaft assembly. Then go

to Step 4.

NO :

There is no action to be taken.

STEP 4. Retest the system.

Q: Is the abnormal noise eliminated?

YES :

The procedure is complete.

NO :

Repeat from Step 1.

INSPECTION PROCEDURE 4:Noise Due to Excessive Wheel Play in Turning Direction

DIAGNOSIS

STEP 1. Check for play in the inner shaft and side
gear serration, the driveshaft and side gear, or
the driveshaft and drive flange.

Q: Is play found?

YES :

Adjust or replace the part. Then go to Step

NO :

The procedure is complete.

STEP 2. Retest the system.

Q: Is the abnormal noise eliminated?

YES :

The procedure is complete.

NO :

Repeat from Step 1.

INSPECTION PROCEDURE 5: Constant Noise

DIAGNOSIS

STEP 1. Check the oil level.

Remove the filler plug and check the gear oil level.
Q: Is the gear oil level more than 8 mm (0.3 inch) below the

bottom of the filler plug hole?
YES : Check the oil leakage from differential carrier, and

repair if necessary. Then, refill Hypoid gear oil API
classification GL-5 or higher; Above

−23°C(−10°F):

SAE 90, 85W-90, 80W-90, From

−34 to −23°C(−30 to

−10°F): SAE 80W, 80W-90, Below −34°C(−30°F):

SAE 75W. Then go to Step 9.

NO : Go to Step 2.

AC000439

UPPER LIMIT

LOWER LIMIT

8 mm (0.3 in)

Content .. 447 448 449 450 ..