1998 OPEL FRONTERA Back

4A2A–30
DIFFERENTIAL (REAR 220mm)
3. After measuring dimensions of each of the above
sections, proceed with the adjustment in the following
manner:
Adjust the clearance to satisfy the equation below.
{(F – B) + G – H}=0.05 – 0.20 mm
Also, select the thrust washers so that the
dimensional difference between the back surfaces of
the left and right pressure rings to the thrust washers
is 0.05mm or less.
Thickness : 1.5mm (0.059 in)
1.6 mm(0.063 in)
1.7 mm(0.067 in)
NOTE: When assembling the parts, apply recommended
gear oil sufficiently to each of the parts, especially, to the
contact surfaces and sliding surfaces.
1. Install Differential cage B.
2. Install Thrust washer.
3. Install Spring disc.
When assembling the spring disc, make sure the
mounting direction is correct as shown in figure.
425RS068
Legend
(1) Friction Plate
(2) Spring Disc
(3) Friction Disc
4. Inatall Spring disc.
5. Inatall Friction plate.
6. Inatall Friction disc.
7. Inatall Friction plate.
8. Inatall Friction disc.
9. Inatall Pressure ring.
10. Inatall Side gear.
11. Inatall Pinion and pinion shaft.
12. Inatall Side gear.
13. Inatall Pressure ring.
14. Inatall Friction disc.15. Inatall Friction plate.
16. Inatall Friction disc.
17. Inatall Friction plate.
18. Inatall Spring disc.
When assembling the spring disc, make sure the
mounting direction is correct.
19. Inatall Spring disc.
20. Inatall Thrust washer.
21. Inatall Differential cage A.
22. Inatall Screw.
Matching the guide marks of the differential cages A
and B, tighten the screws evenly in the diagonal
order.
425RS055

DIFFERENTIAL (REAR 244mm)
4A2B–3
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.

4A2B–10DIFFERENTIAL (REAR 244mm)
Disassembled View
415RW002
Legend
(1) Flange Nut and Washer
(2) Flange
(3) Oil Seal
(4) Oil Seal Slinger
(5) Outer Bearing
(6) Outer Bearing Outer Race
(7) Diff Carrier
(8) Bearing Cap
(9) Bolt(10) Inner Bearing Outer Race
(11) Collapsible Spacer
(12) Inner Bearing
(13) Adjust Shim (Pinion Position)
(14) Drive Pinion Shaft
(15) Adjust Shim (Diff Cage Assembly)
(16) Diff Preload/Backlash
(17) Side Bearing
(18) Side Bearing Outer Race

4A2B–14DIFFERENTIAL (REAR 244mm)
4. Set the dial indicator 5–8840–0126–0 to “0”.
Place it on the mounting post of the gauging arbor
with the contact button touching the indicator pad.
Force the dial indicator downward until the needle
has made a half turn clockwise. Tighten down the
dial indicator in this position.
425RS020
Legend
(1) Dial Indicator
(2) Ganging Arbor
(3) Plunger
(4) Gauge Plate
5. Position the plunger on the gauge plate. Move the
gauging arbor slowly back and forth and locate
the position at which the dial indicator shows the
greatest defection. At this point, once again set
the dial indicator to “0”. Repeat the procedure to
verify the “0” setting.
425RS021
6. After the ZERO setting is obtained, rotate the
gauging arbor until the dial indicator rod does not
touch the gauging plate. Record the number the
dial indicator needle points to.
425RS022
Legend
(1) Example=Dial indicator reading od 0.085
7. Record the pinion depth code on the head of the
drive pinion. The number indicates a necessary
change in the pinion mounting distance. A plus
number indicates the need for a greater mounting
distance (which can be achieved by decreasing
the shim thickness). A minus number indicates
the need for a smaller mounting distance (which
can be achieved by increasing the shim
thickness). If examination reveals pinion depth
code “0”, the pinion is “nominal”.
425RS023

DIFFERENTIAL (REAR 244mm)
4A2B–17
4. Using punch 5–8840–2293–0, stake the flange
nut at two points.
NOTE: When staking, be sure to turn the nut to ensure
that there is no change in bearing preload. Make sure of
preload again as instructed in 3).
425RW062
11. Adjust ring gear backlash.
1. Attach the side bearing to the differential
assembly without shims by using installer
5–8840–2570–0 and grip 5–8840–0007–0.
425RW063
2. Insert the differential cage assembly with bearing
outer races into the side bearing bores of the
carrier.
425RS030
3. Using two sets of feeler gauges, insert a feeler
stock of sufficient thickness between each
bearing outer race and the carrier to remove all
end play. Make certain the feeler stock is pushed
to the bottom of the bearing bores.
Mount the dial indicator 5–8840–0126–0 on the
carrier so that the indicator stem is at right angles to
a tooth on the ring gear.
425RW049

4A2B–18DIFFERENTIAL (REAR 244mm)
4. Adjust feeler gauge thickness from side to side
until ring gear backlash is in the specified range.
Backlash: 0.13– 0.2mm (0.005– 0.008in)
425RS032With zero end play and correct backlash
established, remove the feeler gauge packs,
determine the thickness of the shims required and
add 0.05 mm (0.002 in) to each shim pack to
provide side bearing preload. Always use new
shims.
5. Remove side bearing by using remover
5–8840–2587–0 and adapter 5–8840–2576–0.
415RW041
12. Install the side bearings together with the selected
shims by using installer 5–8840–2570–0 (2) and grip
5–8840–0007–0 (1).
425RW032
13. Install side bearing outer race.
14. Install differential cage assembly.
15. Align the setting marks (1) applied at disassembly
then install the bearing cap.
425RS035

4B1–11 DRIVE LINE CONTROL SYSTEM (SHIFT ON THE FLY)
Functions of Indicator Lamp
Indication of vehicle condition : Indicator lamp is
controlled by 4WD control unit and shows vehicle
conditions as below.
Indicator
Vehicle condition4WD switchTransfer position
switchFront axle switch
Off2WDOff (Close)2WD (Open)2WD (Open)
On4WDOn (Open)4WD (Close)4WD (Close)
Blink (2Hz)OperatingOn (Open)4WD (Close)2WD (Open)
Off (Close)2WD (Open)4WD (Close)
Blink (4Hz)Stop operatingOn (Open)2WD (Open)2WD (Open)
Off (Close)4WD (Close)4WD (Close)
Bulb check :To check the bulb of indicator lamp, the
indicator lamp comes on when ignition key is turned on,
and goes off when the engine is started.
Retrials from 2WD to 4WD :In cold weather or under
high speed condition, the gear shifting (engagement)sometimes does not complete by 3 trials. In such case,
the indicator lamp inform driver of this incident as
aforementioned chart (shown at Retrial in Outline of shift
on the fly system).
Diagnosis
Before Judging That Troubles Occur
(Unfaulty mode)
When Switching from 2WD to 4WD
1.In case that blinking frequency of the 4WD
indicator changes from 2Hz to 4Hz.
When heavy synchronization load is needed, the
motor actuator tries the shifting transfer gear three
times including the activation shifting. While the
motor actuator tries shifting, the indicator blinks by
2Hz. If the third shifting fails, the indicator’s blinking
changes from 2Hz to 4Hz at the same time that the
motor actuator shifted back to 2WD.
Heavy synchronization load occurs by:
extremely lower temperature.
higher speed, rotation difference of wheels during
cornering.
Solution 1: Operate again after stop the vehicle or
slow down.
2.In case that the 4WD indicator continues blinking
by 2Hz for more than 11.5 seconds.
When there is rotation difference of wheels or there
is phase difference between front wheels and axles,
it is difficult to connect front wheels to front axles. The
blinking by 2Hz shows that shifting the transfer gear
or connecting the front wheels is in the middle of
operating. In above case, the indicator’s blinking by
2Hz shows that connecting the front wheels is not
completed (because the indicator’s blinking changes
to 4Hz when the shifting transfer gear is impossible.).
And removal of rotation or phase difference make
connecting the front wheels possible.
Solution 2: When vehicle is running, drive
straight ahead while accelerating and
decelerating. When vehicle is at a stop, move the
vehicle forward and backward from 2 to 3 meters.When switching from 4WD to 2WD
1.In case that the 4WD indicator continues blinking
by 2Hz .
The 4WD indicator continues blinking by 2Hz until
both shifting the transfer gear and disconnecting the
front wheels are completed when switching 4WD to
2WD. When driveline is loaded with torsional torque,
the shifting transfer gear and disconnecting front
wheels are impossible. In this case, removal of
torsional torque on driveline make the shifting
transfer gear and disconnecting front wheels
possible.
Solution 3: When vehicle is running, drive
straight ahead while accelerating and
decelerating. When vehicle is at a stop, move the
vehicle forward and backward from 2 to 3 meters.
2.In case that the 4WD indicator’s blinking changes
from 2Hz to 4Hz.
Check the position of transfer lever. Is it at “4L”
position? In view of the shifting mechanism of
transfer, the gear shifting from 4WD to 2WD at “4L”
condition is impossible.
Solution 4: Push the 4WD switch to 4WD, shift the
transfer lever to “High” position and re–operate
the 4WD switch to 2WD.

4B2–3 DRIVE LINE CONTROL SYSTEM (TOD)
detects the slip 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 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.