1998 OPEL FRONTERA ABS

4A2A–6
DIFFERENTIAL (REAR 220mm)
11. Install the lateral rod fixing nut to the axle housing.
12. Install the stabilizer linkage mounting nut to the axle
housing.
13. Install the shock absorber fixing nut to the axle
housing.
14. Install brake tube flare nut, Refer to Disk Brakes in
Brake section.15. Install ABS connector and bracket (ABS model only).
16. Connect breather hose.
17. Install parking brake cable, Refer to Parking Brakes in
Brake section.
18. Bleed brakes. Refer to Hydraulic Brakes in Brake
section.
Axle Shaft
Axle Shaft and Associated Parts
420RY00005
Legend
(1) Brake Caliper
(2) Brake Disc
(3) Wheel Pin
(4) Axle Shaft Assembly
(5) Back Plate
(6) Parking Brake Assembly(7) Bearing Holder
(8) Bearing
(9) Retainer
(10) Snap Ring
(11) Bolt
(12) Nut
(13) Antilock Brake System (ABS) Speed Sensor
Removal
1. Raise the vehicle.
2. Remove tires and wheels. Refer to Wheel in Steering
section.3. Remove brake caliper. Use a wire to attach the brake
caliper to the frame. Refer to Disk Brakes in Brake
section.
4. Remove brake disc.
5. Remove ABS sensor.
6. Remove Parking brake assembly. Refer to Parking
Brakes in Brake section.

DIFFERENTIAL (REAR 220mm)
4A2A–11
Differential Assembly
Differential Assembly and Associated Parts
425RW055
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–4DIFFERENTIAL (REAR 244mm)
Diagnosis
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 of the
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
(3.5kg/cm
2, 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 noise 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. Driving 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 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.

DIFFERENTIAL (REAR 244mm)
4A2B–5
Axle Housing
Axle Housing and Associated Parts
420RY00007
Legend
(1) Coil Spring and Insulator
(2) Axle Housing Assembly
(3) ABS Speed Sensor and Harness (if so
equipped)
(4) Nut
(5) Parking Brake Cable
(6) Bolt and Nut
(7) Antilock Brake System (ABS) Connector and
Bracket (if so equipped)(8) Bolt and Nut
(9) Nut
(10) Differential Assembly
(11) Axle Shaft Assembly
(12) Brake Disc
(13) Brake Pipe
(14) Brake Caliper
(15) Nut
(16) Breather Hose
(17) Flare Nut
Removal
1. Raise the vehicle and support it with suitable safety
stands.
The hoist must remain under the rear axle housing.
2. Drain brake fluid. Refer to Hydraulic Brakes in Brakes
section.
3. Remove rear wheels and tires. Refer to Wheel in
Suspension section.4. Remove propeller shaft. Refer to Rear Propeller
Shaft in this section.
5. Drain the rear axle oil into a proper container.
6. Remove parking brake cable, release the connection
between the cable fixing clip equalizer. Refer to
Parking Brakes in Brakes section.
7. Move the clip aside and pull out the breather hose.

4A2B–6DIFFERENTIAL (REAR 244mm)
8. Disconnect the ABS connectors (1) and remove the
brackets (2) (if so equipped) attached to the frame
and center link.
350RS001
9. Loosen the brake tube flare nut, remove the clip and
take out the brake tube.
10. Remove the shock absorber fixing nut from the axle
housing.
11. Remove the stabilizer linkage mounting nut from the
axle housing.
12. Remove the lateral rod fixing nut from the axle
housing.
13. Remove the center link mounting bolt and nut from
the axle housing.
14. Remove the trailing link fixing bolt and nut from the
axle housing.
15. Jack down and remove the coil spring and insulator.
16. Axle housing assembly can be separated from the
vehicle on completion of steps 1 – 11.
17. Remove the brake caliper fixing bolt (3), loosen the
flare nut (1), release the clip (2) and take out the brake
caliper together with the flexible hose.
306RS001
18. Remove brake disc.
19. Remove antilock brake system speed sensor fixing
bolt and the clip and bracket (if so equipped) on the
axle housing.
20. Remove the brake pipe clip and fixing bolt on the axle
housing and take out the brake pipe.
21. Remove the bearing holder fixing nut and take out the
axle shaft assembly, be sure not to damage the oil
seal by the spline of the shaft, Refer to Axle Shaft in
this section.
22. Remove differential assembly, refer to Differential
Assembly in this section.
Oil Seal Replacement
Remove the oil seal, carefully not to damage the housing,
and mount new oil seal using oil seal installer
5–8840–2294–0
420RW028
Installation
1. Install differential assembly, refer to Differential
Assembly in this section.
2. Install axle shaft assembly then tighten the bearing
holder mounting nut to the specified torque. Be sure
not to damage the oil seal by the spline of the shaft.
Torque: 74Nꞏm (7.5kgꞏm/54 lb ft)
3. Install brake pipe.
4. Connect antilock brake system (ABS) speed sensor
and harness (if so equipped), refer to Anti–Lock
Brake System in Brake section.
5. Install brake disc.
6. Install brake caliper. Refer to Disk Brakes in Brake
section.
7. Install axle housing assembly.
8. Install coil spring and insulator.
9. Install the trailing link fixing bolt and nut to the axle
housing. For the procedures in items 9–13, refer to
Suspension section.
10. Install the center link bolt and nut to the axle housing.

DIFFERENTIAL (REAR 244mm)
4A2B–7
11. Install the lateral rod fixing nut to the axle housing.
12. Install the stabilizer linkage mounting nut to the axle
housing.
13. Install the shock absorber fixing nut to the axle
housing.
14. Install brake tube flare nut, Refer to Disk Brakes in
Brake section.15. Install ABS connector and bracket (if so equipped).
16. Connect breather hose.
17. Install parking brake cable, Refer to Parking Brakes in
Brake section.
18. Bleed brakes. Refer to Hydraulic Brakes in Brake
section.
Axle Shaft
Axle Shaft and Associated Parts
420RY00005
Legend
(1) Brake Caliper
(2) Brake Disc
(3) Wheel Pin
(4) Axle Shaft Assembly
(5) Back Plate
(6) Parking Brake Assembly(7) Bearing Holder
(8) Bearing
(9) Retainer
(10) Snap Ring
(11) Bolt
(12) Nut
(13) Antilock Brake System (ABS) Speed Sensor
Removal
1. Raise the vehicle.
2. Remove tires and wheels. Refer to Wheel in Steering
section.3. Remove brake caliper. Use a wire to attach the brake
caliper to the frame. Refer to Disk Brakes in Brake
section.
4. Remove brake disc.
5. Remove ABS sensor.
6. Remove Parking brake assembly. Refer to Parking
Brakes in Brake section.

4A2B–12DIFFERENTIAL (REAR 244mm)
Differential Assembly
Differential Assembly and Associated Parts
425RY00016
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.

4B2–3 DRIVE LINE CONTROL SYSTEM (TOD)
condition, determines the optimum torque based on the
feedback control logic, and increases the torque to the
front wheels.
The control unit uses the signal from the throttle position
sensor to predict the future vehicle condition and the
intention of the driver with respect to acceleration and
deceleration, and determines the initial torque distribution
using these data and the information from the speed
sensors.
In case of small circle turning in the parking lot, for
example, the control unit minimizes the clutch pressing
force to restrict a braking phenomenon. When the ABS
becomes active, the control unit optimizes the clutch
pressing force to ensure stable braking.
TOD Indicator Control
The TOD indicator on the instrument panel informs the
driver of the current working status of the transfer unit.
The information consists of two items: the drive mode
(2H, TOD, 4L, transition) and the torque split status of the
TOD (torque distribution level). The indicator can display
occasional errors and corresponding error codes.