1998 OPEL FRONTERA steering

DIFFERENTIAL (FRONT) 4A1–2
Front Drive Axle
Diagnosis
ConditionPossible causeCorrection
Oil Leak At Front AxleWorn or defective oil seal.Replace the oil seal.
Front axle housing cracked.Repair or replace.
Oil Leak At Pinion ShaftToo much gear oil.Correct the oil level.
Oil seal worn or defective.Replace the oil seal.
Pinion flange loose or damaged.Tighten or replace.
Noises In Front Axle Drive Shaft
JointBroken or worn drive shaft joints and
bellows (BJ and DOJ).Replace the drive shaft joints and
bellows.
“Clank” When Accelerating From
“Coast”Loose drive shaft joint to output shaft
bolts.Tighten.
Damaged inner drive shaft joint.Replace.
Shudder or Vibration During
Acceleration
Excessive drive shaft joint angle.Repair.
AccelerationWorn or damaged drive shaft joints.Replace.
Sticking spider assembly (inner drive
shaft joint).Lubricate or replace.
Sticking joint assembly (outer drive
shaft joint).Lubricate or replace.
Vibration At Highway SpeedsOut of balance or out of round tires.Balance or replace.
Front end out of alignment.Align.
Noises in Front AxleInsufficient gear oil.Replenish the gear oil.
Wrong or poor grade gear oil.Replace the gear oil.
Drive pinion to ring gear backlash
incorrect.Adjust the backlash.
Worn or chipped ring gear, pinion
gear or side gear.Replace the ring gear, pinion gear or
side gear.
Pinion shaft bearing worn.Replace the pinion shaft bearing.
Wheel bearing worn.Replace the wheel bearing.
Differential bearing loose or worn.Tighten or replace.
Wanders and PullsWheel bearing preload too tight.Adjust the wheel bearing preload.
Incorrect front alignment.Adjust the front alignment.
Steering linkage loose or worn.Tighten or replace.
Steering gear out of adjustment.Adjust or replace the steering gear.
Tire worn or improperly inflated.Adjust the inflation or replace.
Front or rear suspension parts loose
or broken.Tighten or replace.
Front Wheel ShimmyWheel bearing worn or improperly
adjusted.Adjust or replace.
Incorrect front alignment.Adjust the front alignment.
Worn ball joint or bush.Replace the ball joint or bush.
Steering linkage loose or worn.Tighten or replace.
Steering gear out of adjustment.Tighten or replace.
Tire worn or improperly inflated.Replace or adjust the inflation.
Shock absorber worn.Replace the shock absorber.

DIFFERENTIAL (FRONT) 4A1–6
3. Remove the drain bolt to drain differential oil.
NOTE:
a. During the work, be sure that the diff case is
supported by the jack.
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b. Remove the brake caliper fixing bolt and hang the
caliper. Refer to Front Disc Brake Caliper Assembly
in Brake section.
c. Remove the antilock brake system speed sensor (if
equipped). Refer to Front Wheel Speed Sensor in
Brakes section.
4. Remove the hub assembly (Disc, back plate and
knuckle), refer to Front Hub and Disc in this section.
5. Disconnect the knuckle and the suspension arm.
Refer to Suspension section.
6. Remove steering link and arm assembly, refer to
Steering Linkage in Steering section.
7. Remove suspension crossmember.
8. Remove propeller shaft, refer to Front Propeller Shaft
in this section.
9. Remove protector (Shift on the fly model).
10. Remove breather hose (Shift on the fly model).
11. Remove the hose clip (Shift on the fly model).
12. Disconnect breather hose from front drive axle tube
and disconnect housing (Shift on the fly model).
13. Disconnect vacuum hose from actuator (Shift on the
fly model).14. Disconnect shift switch connector (Shift on the fly
model).
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15. Remove VSV assembly (1) (Shift on the fly model).
NOTE: Be sure not to remove hose and connector from
VSV asm.
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DIFFERENTIAL (FRONT) 4A1–8
5. Tighten the mounting bolt and nut to the specified
torque.
Torque: 152 Nꞏm (15.5kgꞏm/112 lb ft)
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Legend
(1) Frame
(2) Spacer
(3) Washer
(4) Bolt
(5) Nut
6. Install VSV assembly and tighten nuts to specified
torque (Shift on the fly model).
Torque: 8 Nꞏm (0.8kgꞏm/69 lb in)
7. Install the shift switch connector (Shift on the fly
model).
NOTE: Be careful not to permit the entry of dust into the
connector.
8. Install the actuator side of vacuum hose (Shift on the
fly model).
NOTE: Be careful not to permit the entry of dust into the
hose.
9. Connect breather hose and install the hose clip (Shift
on the fly model).
10. Install protector and tighten bolts to specified torque
(Shift on the fly model).
Torque: 26 Nꞏm (2.7kgꞏm/20 lb ft)
11. Install propeller shaft, refer to Front Propeller Shaft in
this section.
12. Install suspension crossmember.
13. Steering link and arm assembly, refer to Steering
Linkage in Steering section.
14. Install hub assembly (Disc, back plate and knuckle),
refer to Front Hub and Disc in this section.

4A2A–8
DIFFERENTIAL (REAR 220mm)
Differential Assembly
Differential Assembly and Associated Parts
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Legend
(1) Bolt and Nut
(2) Axle Shaft Assembly(3) Parking Brake Cable
(4) Differential Assembly
(5) Nut
Removal
1. Jack up and support the frame with stands.
2. Remove the wheel and tire. Refer to Wheel in
Steering section.
3. Drain the differential oil.
4. Remove the propeller shaft. Refer to Rear Propeller
Shaft in this section.
5. Remove the ABS speed sensor(ABS model only).
Refer to 4–Wheel Anti–lock Brake System (ABS) in
Brake section.6. Remove the parking brake cable fastening clip and
disconnect the equalizer section. Refer to Parking
Brakes in Brake section.
7. Remove the bearing holder fixing nuts.
8. Remove axle shaft assembly, be sure not to damage
the oil seal by axle shaft.
9. Remove differential carrier mounting bolts and nuts.
10. Remove differential assembly.

4A2B–8DIFFERENTIAL (REAR 244mm)
Differential Assembly
Differential Assembly and Associated Parts
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Legend
(1) Bolt and Nut
(2) Axle Shaft Assembly(3) Parking Brake Cable
(4) Differential Assembly
(5) Nut
Removal
1. Jack up and support the frame with stands.
2. Remove the wheel and tire. Refer to Wheel in
Steering section.
3. Drain the differential oil.
4. Remove the propeller shaft. Refer to Rear Propeller
Shaft in this section.
5. Remove the ABS speed sensor. Refer to Anti–lock
Brake System in Brakes section.6. Remove the parking brake cable fastening clip and
disconnect the equalizer section. Refer to Parking
Brakes in Brake section.
7. Remove the bearing holder fixing nuts.
8. Remove axle shaft assembly, be sure not to damage
the oil seal by axle shaft.
9. Remove differential carrier mounting bolts and nuts.
10. Remove differential assembly.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–14
How to Clear The Trouble Code
The trouble codes saved to the control unit can be deleted
by the following procedure if the starter switch is being in
the OFF position.
1. Shift the transfer lever to the neutral position between
HIGH and 4L, and short-circuit the self-diagnostic
connector.
NOTE: The neutral position between HIGH and 4L refers
to the point that turns off the TOD indicator lamps.
(However, be sure to check the position before
short-circuiting the self-diagnostic connector.)
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2. Turn on the starter switch while maintaining the state
of step 1, and step on the brake pedal five times within
five seconds from the first step on. (Note that “five
times” includes the first step on). (The TOD indicator
lamps display the 4L mode whenever the brake pedal
is stepped on.)
3. If the conditions shown in steps 1 and 2 are met, clear
the trouble codes saved to the control unit. (After the
codes are completely deleted, the code 12 that
indicates the normal condition is continuously
displayed.)
Precautions on Diagnosis
Replacement of Control Unit
The control unit itself rarely fails. In most cases, the
harnesses have failed (e.q. short-circuit) to cause
secondary troubles. Other cases include that the cause
has been unknown due to intermittent occurrence of
troubles and the troubles are removed accidentally along
with replacement of control unit, resulting in misjudgment
of cause. Therefore, before replacing the control unit,
check the connector joints and whether the unspecified
current flows in the control unit due to short-circuit
between harnesses.Trouble Intermittently Observed
Troubles intermittently observed are mostly attributable
to temporary imperfect connection of harnesses and
connectors.
When such troubles are found, check the associated
circuit according to the following procedure.
1. Check whether improper connectors are plugged in
or connector terminals are completely engaged.
2. Check whether the terminals are deformed or
damaged. If yes, remove the deformation or damage
and connect the terminals securely.
3. It is likely that wires in the harness are falsely broken.
Therefore, in examination of failed harness circuit,
shake the harness for check to such extent that the
harness will not be damaged.
Test Run of Filed TOD Vehicle
If the TOD indicator lamps experienced faulty operation
even once in the past, the failed portion can be identified
by use of the procedure “Diagnosis from Trouble Codes”
or “Trouble Diagnosis Depending on The Status of TOD
Indicator”. If the troubles that are only recognized as
abnormal phenomena of the vehicle by the driver are
observed, conduct the test run in the following procedure
to reproduce the faulty phenomena and diagnose the fault
for each phenomenon.
1. Start the engine, and check that the TOD indicator
lamps are turned on for about two seconds for initial
check; the CHECK lamp goes off; and the TOD
indicator lamps display the specified drive mode. (If
the CHECK lamp starts blinking, read the trouble
codes and identify the failed portion.)
2. While keeping the vehicle standstill, operate the 4WD
switch and shift the transfer lever to change the
modes: 2H mode
TOD mode4L modeTOD
mode
2H mode. Check that the TOD indicator
lamps correctly display the status whenever the
mode is changed. If the transition status is displayed
during the shift operation, run the vehicle a little to
complete shifting.
3. Slowly start the vehicle in the TOD mode, and add the
power to accelerate to at least 40 km/h and maintain
the speed for about two minutes. Apply the brake to
completely stop the vehicle. Repeat this test pattern
at least three times.
4. Turn the steering to the right end (or left end) in the
TOD mode, and slowly start the vehicle and make a
c i r c l e f i v e t i m e s . N e x t , c o n d u c t t h e s a m e t e s t i n t h e 2 H
mode.
5. Slowly start the vehicle in the TOD mode, and
accelerate to at least 40 km/h. Keep the established
speed, carefully change the mode in the sequence
“TOD mode
2H mode TOD mode” while checking
that the shift is complete in each mode change. After
the test, apply the brake to completely stop the
vehicle.
6. Slowly start the vehicle in the TOD mode, and
accelerate to at least 40 km/h. Apply the brake
strongly so that the ABS works, and completely stop
the vehicle.

DRIVE LINE CONTROL SYSTEM (TOD) 4B2–86
Diagnosis from Symptom
Troubles that are not indicated by the warning lamp are
listed in the table below. These troubles are caused by
the faults that cannot be detected by the self-diagnostic
function of the control unit.
If this type of trouble is observed, interview the customer
and conduct test runs to reproduce the trouble,cross-check the reported trouble with the listed
phenomena, and diagnose and analyze the trouble on the
item by item basis.
PhenomenaMajor causeCorrective action
1The tight corner braking is ob-
served when the vehicle is subject
to full steering.The standard tires are not used.
The tire pressure is incorrect.
The tires are worn inuniformity.
The transfer or wiring is
imperfect.
The limited slip differential is
failed.
Check and recondition the ve-
hicle according to Chart 1.
2Even if the 4WD SW is select to the
4WD position, the 4WD mode is not
active, resulting in remarkable rear
wheel spin.The transfer or wiring is
imperfect.
The shift on the fly system is
failed.
Check and recondition the ve-
hicle according to Chart 2.
3When the 4WD SW is select to
the 4WD position, the drive
resistance of the 4WD system is
too large to get sufficient running
speed.
Noised drive line.
The standard tires are not used.
The tire pressure is incorrect.
The tires are worn inuniformity.
The transfer or wiring is
imperfect.
The limited slip differential is
Check and recondition the ve-
hicle according to Chart 1.
4The shift on the fly system (front
axle) generates gear noises.The wiring is imperfect.
The full automatic free wheel
hub is failed.
Check and recondition the ve-
hicle according to Chart 3.
5The braking distance gets long
even when the ABS is active.The wiring is imperfect.
The ABS is failed.
Check and recondition the ve-
hicle according to Chart 4.

4B2–87 DRIVE LINE CONTROL SYSTEM (TOD)
Chart 1The tight corner braking is observed.
Function of circuit—
Fail conditionWhen the vehicle is subject to full steering in the TOD mode, the drive resistance gets
large or the judder occurs. Otherwise, the above phenomenon is observed only when the
brake is applied.
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