Mitsubishi Evolution X. Manual - part 79

DIFFERENTIAL

TSB Revision

REAR AXLE

27-3

CONSTRUCTION DIAGRAM

DIFFERENTIAL

M2270001000548

The AYC differential is adopted, and has the follow-
ing features:

• The AYC differential consists of differential mech-

anism, acceleration/deceleration gear and two 
pairs of wet multi-plate clutch.

• In order to increase torque transfer amount, 

shaft-to-shaft coupling, which directly transmits 
torque between LH and RH wheels, has been 
adopted for the AYC differential.

• In order to achieve shaft-to-shaft coupling, a plan-

etary gear has been adopted for the differential 
mechanism.

• Cornering ability: When the torque transfer 

amount is increased between LH and RH wheels, 
the yaw moment is also increased to raise the 
cornering limit, as well as to reduce understeer 
characteristics.

• Traction ability: Traction ability (LSD effect) is 

increased when the rear inner wheel looses con-
tact with the ground during high-gravity cornering, 
or when the road conditions for LH and RH 
wheels largely differ.

NOTE: 

.

•

For the AYC (Active Yaw Control), refer to 
GROUP 22A 

−

 Super All Wheel Control (S-AWC) 

−

 Information of construction and operation 

P.22A-6

.

AC706664

ETJ

EBJ

AB

AC608248

ETJ

AYC differential

Rear driveshaft
(LH)

Rear driveshaft
(RH)

Rear wheel bearing

Oil seal

Magnetic
encoder

Rear wheel
hub assembly

Magnetic encoder
protection cover

Rear
driveshaft
nut

Split pin

Rear wheel
hub assembly

DIFFERENTIAL

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REAR AXLE

27-4

SPECIFICATIONS

DIFFERENTIAL

DIFFERENTIAL MECHANISM

When the vehicles turns, admits the revolution differ-
ence between inner wheel and outer wheel.

ACCELERATION/DECELERATION GEAR

Have the revolution speed of right and left wet 
multi-plate clutch to accelerate or decelerate as 
opposed to the revolution speed of right wheel.

WET MULTI-PLATE CLUTCH

Have the torque to move from high speed wheel to 
low speed wheel.
LH clutch operate: deceleration gear have the torque 

to move RH wheel to LH wheel.

RH clutch operate: acceleration gear have the torque 

to move LH wheel to RH wheel.

The movement of torque is dependent on pushing 
force of the clutch.

Item

Specification

Differential type

AYC differential

Reduction gear type

Hypoid gear

Reduction ratio

3.307

Number of teeth

Drive gear

43

Drive pinion

13

Bearing (Outside diameter 

× 

inside diameter) mm (in)

Side

72 

× 37 (2.8 × 1.5) <LH>,  

92 

× 67 (3.6 × 2.6) <RH>

Front

62 

× 25 (2.4 × 1.0)

Rear

72 

× 35 (2.8 × 1.4)

AC211326AC

LH clutch

RH clutch

Wet multi-plate clutch

Differential mechanism
(Planetary gear)

Input
gear

Overdrive
gear

Reduction
gear

Acceleration/deceleration gear

DIFFERENTIAL

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REAR AXLE

27-5

AYC DIFFERENTIAL MECHANISM

When high speed clutch is pushed, the driving power always 
moves from high speed side to low speed side, and controls 
the driving power with the aid of the property which the move-
ment of driving power is proportional to the pushing force of 
clutch.
In AYC differential, acceleration/deceleration gear always 
engages, and toward to input speed from the differential mech-
anism, LH clutch engaging deceleration gear rotates in low 
speed, and RH clutch engaging acceleration gear rotates in 
high speed.
In other hand, the housing side of RH/LH clutch is integrated to 
rear RH axle and if RH or LH clutch is operated, the driving 
power can be moved to right or left.

THE FLOW OF DRIVING POWER

1. LH CLUTCH OPERATE

In order to boost the driving power of LH wheel, when LH 
clutch is operated, a part of the driving power of RH wheel 
flows to the differential mechanism, the driving power of LH 
wheel is boosted. The result of this, the yaw moment occurs 
in a right to the vehicle.

2. RH CLUTCH OPERATE

In order to boost the driving power of RH wheel, when RH 
clutch is operated, a part of the driving power of LH wheel 
flows to the differential mechanism, the driving power of RH 
wheel is boosted. The result of this, the yaw moment occurs 
in a left to the vehicle.

AC310373

High speed
side

Low speed
side

Pushing
force

Pushing
force

Driving power moves

LH
clutch

RH
clutch

Differential
mechanism

Acceleration/deceleration gear

AC

AC310374AC

LH clutch

Driving
power
(small)

Driving
power
(large)

Turning
direction

Yaw
moment

AC310375 AC

RH
clutch

Driving
power
(small)

Driving
power
(large)

Turning
direction

Yaw
moment

DIFFERENTIAL

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REAR AXLE

27-6

DIFFERENTIAL MOUNT

The front side of the differential carrier assembly is 
installed to the rear suspension crossmember via the 
differential mount bracket (LH/RH), and the rear side 
of the assembly is installed via the differential mount 
bracket (AYC differential), differential support 
bracket, and rear differential mount insulator. As 
described above, 3-point support and optimization of 
bushing position for the differential mount are estab-
lished, reducing vibration and noise.

AC704692 AB

Differential support
bracket

Differential mount
bracket

Differential mount
bracket (LH)

Differential mount
bracket (RH)

Differential carrier
assembly

Rear suspension
crossmember

Rear differential
mount insulator

Lower stopper

Upper stopper