1999 MITSUBISHI LANCER EVOLUTION VI differential

27-1
REAR AXLE
CONTENTS
GENERAL 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Outline of Change 2. . . . . . . . . . . . . . . . . . . . . . . . .
SERVICE SPECIFICATIONS 2. . . . . . . . . . . . . .
LUBRICANT 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOLS 3. . . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING 4. . . . . . . . . . . . .
ON-VEHICLE SERVICE
31. . . . . . . . . . . . . . .
Rear Axle Total Backlash Check 31. . . . . . . . . . .
Gear Oil Level Check 31. . . . . . . . . . . . . . . . . . . .
Gear Oil Change 32. . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Level Check 33. . . . . . . . . . . . . . . . . . . . . . . . Bleeding 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AYC Operation Check 34. . . . . . . . . . . . . . . . . . . .
Hydraulic Pressure Check 35. . . . . . . . . . . . . . . . .
Differential Carrier Oil Seal
Replacement 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wheel Speed Sensor Output Voltage
Measurement 37. . . . .
Action When Battery Runs Out 38. . . . . . . . . . . .
HYDRAULIC UNIT
39. . . . . . . . . . . . . . .
SENSOR RELAY
41. . . . . . . . . . . . . . .
AYC-ECU 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REAR AXLE – General / Service Specifications / Lubricant27-2
GENERAL
OUTLINE OF CHANGE

The descriptions of the service procedures for the AYC system including the troubleshooting using
an MUT-II tester has been incorporated.
SERVICE SPECIFICATIONS

ItemsStandard valueLimit
Rear axle total backlash mm–5
Pressure generated by hydraulic unit MPa0 – 1.6–
Wheel bearing axial play mm–0.05
Wheel bearing rotation starting torque Nm–1.0 or less
LUBRICANT

ItemsSpecified lubricantCapacity
Gear oilTorque
transfer
differential
DifferentialHypoid gear oil API classification GL-5 or higher
SAE viscosity No. 90, 80W0.41 ± 0.02

differentialTorque transfer
mechanismMITSUBISHI GENUINE DIA QUEEN AYC FLUID0.700
0.05

Hydraulic piping fluidDia Queen ATF SPII or equivalent1

Torque transfer mechanism oil seal lipsVaselineAs required

REAR AXLE – Special Tools27-3
SPECIAL TOOLS
ToolNumberNameUse
MB991502MUT-II sub-
assemblyInspection of AYC
(diagnosis display by MUT-II)
MB991529Diagnosis code
check harnessInspection of AYC
(diagnosis display by AYC warning lamp)
MD998330
(MD998331)Oil pressure
gauge
(2,942 kPa)Hydraulic pressure measurement

MB991705Hose adapter
MB990925Bearing & oil seal
installer setPressfitting of oil seal
MB991115Oil seal installerPressfitting of oil seal
(used in combination with MB990938)
MD998812Installer capPressfitting of oil seal nism of vehicles with AYC>
MD998813Installer 100
MD998829Installer adapter
(60)

REAR AXLE – Troubleshooting 27-23
INSPECTION PROCEDURE 4
AYC warning lamp remains lit up after the engine has
started.
Probable cause
The AYC warning lamp ON circuit is probably short-circuited.
Defective combination meter

Defective harness (short-circuit)

Defective AYC-ECU
NOTE
This symptom is limited only when the communication with MUT-II is possible with AYC-ECU power supply
in normal condition and the diagnosis code is correct.
OK
Replace combination meter.
NO
Check the harness between AYC
warning lamp and AYC-ECU.NG
Repair
Does the AYC warning lamp goes out
when the B-96 AYC-ECU connector
is disconnected?YESReplace AYC-ECU.
INSPECTION PROCEDURE 5
AYC is inoperative.
Unable to start or accelerate on slippery road surfaces.
Probable cause
The hydraulic oil level is probably low, there is an oil leak, the hydraulic unit is defective,
or the torque transfer differential is defective.
Low hydraulic oil level

Oil leak

Defective hydraulic unit

Defective torque transfer differential
NOTE
This symptom is limited only when the diagnosis code is correct.
NG
Replace the hydraulic unit.
NG
Replace the torque transfer differential.
Check the trouble symptom.
NG
Replace AYC fluid.
OK
Correct
Check the trouble symptom.NO
Replace the torque transfer differential.
OK
Is foreign matter trapped in the hydrau-
lic line?YES
Repair
OK
Check the AYC for operation.
(Refer to P.27-34.)OKCheck the AYC fluid.
NG
Add hydraulic oil.
NG
Check hydraulic pressure..
(Refer to P.27-35.)NGBleed the system of air.
(Refer to P.27-34.)
Check the hydraulic oil level.NGCheck for oil leak.OK
Repair

REAR AXLE – Troubleshooting 27-24
INSPECTION PROCEDURE 6
Rear tires are noisy during low-speed cornering.
Vehicle skews.
Probable cause
The hydraulic unit or torque transfer differential is probably defective.
Defective hydraulic unit

Defective torque transfer differential
NOTE
This symptom is limited only when the diagnosis code is correct.
NG
Replace the hydraulic unit.
NG
Replace the torque transfer differential.
Check the trouble symptom.
NG
Replace AYC fluid.
OK
Correct
Check the trouble symptom.NO
Replace the torque transfer differential.
OK
Is foreign matter trapped in the hydrau-
lic line?YES
Repair
Check the AYC for operation..
(Refer to P.27-34.)OKCheck the AYC fluid.
NG
Check hydraulic pressure.
(Refer to P.27-35.)NGBleed the system of air..
(Refer to P.27-34.)

REAR AXLE – Troubleshooting 27-27
ACTUATOR TEST REFERENCE TABLE
The following items can be tested by driving the corresponding actuator forcibly using the MUT-II.
Item No.Check itemChecking requirementsNormal value
10Air bleedingSupply current to proportioning
valve in accordance with steering
angle to operate directional valve.No air is to be bled from the
bleeder plug on the torque transfer
differential.
11Oil level checkLet the directional valve operate to
left and right 20 times.To be checked by oil level in
reservoir tank.
12Electric pump operationLet the electric pump operate for 5
seconds.Operation sounds of the electric
pump are to be heard.
13Clutch operation (left)Let the directional valve operate to
supply the maximum pressure to the
left clutch.The operation conditions are to be
checked by the speed difference
between left and right rear wheels
with the wheels raised. For details,
refer to AYC Operation Check on
P.27-34.
14Clutch operation (right)Let the directional valve operate to
supply the maximum pressure to the
right clutch.The operation conditions are to be
checked by the speed difference
between left and right rear wheels
with the wheels raised. For details,
refer to AYC Operation Check on
P.27-34.
15Control OFFTurn off the electric pump relay to
deactivate AYC control.During the test run, some
differences are to be recognized in
running behaviors between when
the system is ON and when it is
OFF.
NOTE
(1) The actuator test is feasible only when the following requirements are all satisfied.

All of inputs from four wheel speed sensors show 20 km/h or lower.

No system failure is registered.

The steering angle is within ±30 deg. from the neutral position.
(2) The actuator test comes to an end when either of the following conditions is met since the forced
actuation is canceled.

Either of inputs from four wheel sensors shows higher than 20 km/h (with exception of Item
No.15 “Control OFF”).

Some trouble with the system is registered.

Forced activation time expires.

MUT-II is removed.

The clear key of MUT-II is operated.

REAR AXLE – On-vehicle Service 27-31
ON-VEHICLE SERVICE

REAR AXLE TOTAL BACKLASH CHECK
If the drive system roars or the vehicle vibrates, use the
following procedure to measure total backlash in the rear
axle. Based on the measurement taken, determine whether
the differential carrier assembly needs to be removed or not.
1. Place the shift lever in the neutral position and operate
the parking brake.
2. Turn the propeller shaft fully clockwise and make an
alignment mark on the companion flange dust cover and
gear carrier.
3. Turn the propeller shaft fully counterclockwise and
measure the deviation between the alignment marks.
Limit: 5 mm
4. If the backlash exceeds the limit, replace the differential
carrier assembly.
GEAR OIL LEVEL CHECK
DIFFERENTIAL
1. Remove the filler plug.
2. Check that the gear oil level is within the specified range
from the bottom end of the filler plug hole.
Standard value (A): 6 mm
3. If the gear oil level exceeds the standard value, add the
specified gear oil up to the bottom end of the filler plug
hole.
Specified gear oil:
Hypoid gear oil API classification GL-5 or higher
SAE viscosity Number 90, 80W.
NOTE
10C or more: #90, less than 10C: #80
4. Fit the filler plug and tighten it to the specified torque.
Alignment marks
Filler plug
49 Nm
Gear oil
Upper
limit
Lower
limit

REAR AXLE – On-vehicle Service 27-32
TORQUE TRANSFER MECHANISM
1. Remove the filler plug.
2. Check that the gear oil level is up to the bottom end
of the filler plug hole.
3. If the gear oil level is lower than the bottom end of the
filler plug hole, add the specified gear oil up to the bottom
end of the filler plug hole.
Specified gear oil:
MITSUBISHI GENUINE DIA QUEEN SUPER AYC
FLUID
4. Fit the filler plug and tighten it to the specified torque.
GEAR OIL CHANGE
DIFFERENTIAL
1. Remove the drain plug to discharge the gear oil.
2. Fit the drain plug and tighten it to the specified torque.
Tightening torque: 49 Nm
3. Remove the filler plug and add the specified gear oil
up to the bottom end of the filler plug hole.
Specified gear oil:
Hypoid gear oil API classification GL-5 or higher
SAE viscosity Number 90, 80W.
Quantity used: 0.41 ± 0.02

NOTE
10C or more: #90, less than 10C: #80
4. Fit the filler plug and tighten it to the specified torque.
Filler plug
49 Nm
Gear oil
Filler plug
49 Nm
Gear oil
Drain plug