2-1

POWER TRAIN

CONTENTS

CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 System Structure . . . . . . . . . . . . . . . . . . . . . . . . . 16

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Oil Pressure Unit . . . . . . . . . . . . . . . . . . . . . . . . . 18
Electronic Control System . . . . . . . . . . . . . . . . . 20
MANUAL TRANSMISSION . . . . . . . . . . . . . . . . 3
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 PROPELLER SHAFT . . . . . . . . . . . . . . . . . . . . 27
Sectional View . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
FRONT AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4WD System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Power Train . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 REAR AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Transmission Control . . . . . . . . . . . . . . . . . . . . . 11
DIFFERENTIAL . . . . . . . . . . . . . . . . . . . . . . . . . 30
ACTIVE CENTER DIFFERENTIAL (ACD)
AND ACTIVE YAW CONTROL (AYC) . . . . . . . . 12 DIFFERENTIAL MOUNT . . . . . . . . . . . . . . . . . 33
Description of Structure and Operations . . . . 16
2-2 POWER TRAIN - Clutch

CLUTCH
SPECIFICATIONS
Items Specifications

Engine model 4G63-DOHC-Intercooler Turbocharger

Clutch disc type Dry single plate type

Clutch disc facing diameter O.D. I.D. mm 240 160

Clutch cover type Diaphragm spring pull type

Clutch cover set load N 9,320 ± 750

Control system Hydraulic type

Release cylinder I.D. mm 20.64

Master cylinder I.D. mm 15.87

Clutch fluid Brake fluid DOT 3 or DOT 4

CLUTCH CONTROL CONFIGURATION

<L.H.drive vehicles> Reservoir hose Master cylinder member assembly

Clutch hose

Clutch pipe

Clutch master cylinder

Clutch pedal

Reservoir hose Master cylinder member assembly

Clutch release
cylinger Clutch pipe

<R.H.drive vehicles> Clutch master cylinder

Clutch pipe Clutch pedal

Clutch hose

Clutch release cylinger

 POWER TRAIN - Manual Transmission 2-3
MANUAL TRANSMISSION
The manual transmission is a W5M5 transmission. This transmission incorporates the following changes
from the F5M4 type transmission mounted to GALANT.
D With the incorporation of 4WD, the center differential has been positioned at the front differential
of the 2WD, and the front differential has been positioned inside the transfer.
D The kinetic performance has been improved by setting a helical gear LSD for the front differential.
<RS, RS II: Option>
D With the adoption of the active center differential (ACD), an hydraulic multi plate clutch has been
adopted for the transfer limited slip differential. <RS, RS II: Option> (Refer to P.2-17 for details
of the hydraulic multi plate clutch.)
SPECIFICATIONS
Item Specifications
Classification RS, RS II RS, RS II (Super cross gear specifications)
Transmission type W5M51
Engine type 4G63-DOHC-T/C
Transmission type 5 steps forward, 1 step reverce, always in contact)
Gear ratio 1st 2.785 ←
2nd 1.950 ←
3rd 1.407 1.444
4th 1.031 1.096
5th 0.720 0.825
Reverse 3.416 ←
Final deceleration ratio 4.529 ←
Helical gear LSD (Front differential) No Yes
Transfer Deceleration ratio 3.307 ←
Limited slip differential VCU or hydraulic multi ←
plate clutch (ACD)
2-4 POWER TRAIN - Manual Transmission

SECTIONAL VIEW
W5M51 <Vehicle with VCU>

4 5

1 2 3
6

19 18 17 16 15 14

20
10
11
13

12

1. 4th gear 11. Transfer cover

2. 3rd - 4th synchronizer 12. Hypoid pinion
3. 3rd gear 13. Center differential
4. Transmission case 14. 1st gear
5. Clutch housing 15. 1st - 2nd synchronizer
6. Clutch release bearing retainer 16. 2nd gear
7. Input shaft 17. 5th gear
8. Output shaft 18. 5th - reverse synchronizer
9. Front differential 19. Reverse gear
10. Viscous coupling unit (VCU) 20. Reverse idler gear
 POWER TRAIN - Manual Transmission 2-5
W5M51 <Vehicle with ACD>

4 5

1 2 3

21 20 19 18 17 16

22
10

11
15 13 12

14

1. 4th gear 12. Piston

2. 3rd - 4th synchronizer 13. Transfer hydraulic case
3. 3rd gear 14. Hypoid pinion
4. Transmission case 15. Center differential
5. Clutch housing 16. 1st gear
6. Clutch release bearing retainer 17. 1st - 2nd synchronizer
7. Input shaft 18. 2nd gear
8. Output shaft 19. 5th gear
9. Front differential 20. 5th - reverse synchronizer
10. Clutch housing 21. Reverse gear
11. Transfer cover 22. Reverse idler gear
2-6 POWER TRAIN - Manual Transmission

W5M51 <Vehicle with Helical Gear LSD and VCU>

4 5

1 2 3
6

19 18 17 16 15 14

20
10
13 11

12

1. 4th gear 11. Transfer cover

2. 3rd - 4th sychronizer 12. Hypoid pinion
3. 3rd gear 13. Center differential
4. Transmission case 14. 1st gear
5. Clutch housing 15. 1st - 2nd sychronizer
6. Clutch release bearing retainer 16. 2nd gear
7. Input shaft 17. 5th gear
8. Output shaft 18. 5th - reverse synchronizer
9. Front differential (Helical gear LSD) 19. Reverse gear
10. Viscous coupling unit (VCU) 20. Reverse idler gear
 POWER TRAIN - Manual Transmission 2-7
W5M51 <Vehicle with Helical Gear LSD and ACD>

4 5

1 2 3
6

21 20 19 18 17 16

22
10
11
15 13 12

14

1. 4th gear 12. Piston

2. 3rd - 4th sychronizer 13. Transfer hydraulic case
3. 3rd gear 14. Hypoid pinion
4. Transmission case 15. Center differential
5. Clutch housing 16. 1st gear
6. Clutch release bearing retainer 17. 1st - 2nd sychronizer
7. Input shaft 18. 2nd gear
8. Output shaft 19. 5th gear
9. Front differential (Helical gear LSD) 20. 5th - reverse synchronizer
10. Clutch housing 21. Reverse gear
11. Transfer cover 22. Reverse idler gear
2-8 POWER TRAIN - Manual Transmission

4WD SYSTEM
The 4WD system is a center differential full-time 4WD with limited slip differential.
The center differential has been positioned at the front differential of the 2WD transmission, and the
front differential has been positioned inside the transfer. The limited slip differential of the center differential
has been positioned at the back of the front differential in the transfer.
For the limited slip differential of the center differential, a viscous coupling unit (VCU) or active center
differential (ACD) has been adopted.

Engine

Transfer

Limited slip
differential
Center differential

Front differential

Rear differential
 POWER TRAIN - Manual Transmission 2-9
POWER TRAIN
Helical Gear LSD
The helical gear LSD is composed of four long pinions, four short pinions, three thrust washers, side
gears A and B, and cases A and B.
The long pinions are in contact with the side gear B and short pinions, while the short pinions are in
contact with the side gear A and long pinions.

Case B
Short pinion
Thrust washer

Side gear B

Long pinion
Side gear A

Case A

Power Flow
Operations in forward driving
During forward driving, as the differential case and and drive shaft rotate at the same speed, they
rotate at the assembly without the inside of the differential moving.
The driving force at this time will be transmitted as follows.
Differential case Long and short pinions Side gears A and B Drive shaft

Driving power
Differential case Side gear B

Short pinion

Long pinion

Side gear A
2-10 POWER TRAIN - Manual Transmission

Operations during differential (when there is rotational difference between the left and right
wheels)
When the frictional coefficient of the left and right wheels are more or less equal, and a slight rotational
difference occurs at the left and right wheels (normal turning), rotational difference will also occur
between side gears A and B. In this case, while the long pinions and short pinions mutually rotate
in the reverse direction, the vicinity of side gears A and B revolves and absorbs the speed difference.
In this way, like normal differential, the high speed side accelerates for the revolved amount in respect
to the revolution speed of the differential case,while the low speed side rotates in the decelerated
state and performs differential.

Differential case Driving power

Side gear B

Revolution

Low speed
side
Autorotation

High speed side

Long pinion

Side gear A Short pinion

Autorotation

Operations during Limited Slip Differential

When the loads of the left and right wheels become unbalanced due to changes in road surface
conditions and sudden turning, the driving torque of side gears A and B will differ.
As mentioned earlier, because side gears A and B are in contact via the respective long and short
pinions, the gears influence each other, resulting in contact reaction force (F and f) between the
long pinion and side gear B, and the short pinion and side gear A.
The separating force (Ft and ft) in the axial direction of the contact reaction force causes side gears
A and B to be pushed and extended. From this force, side gears A and B are pushed against the
thrust washer (case) and friction occurs.
The separating force (Fr and fr) in the radial direction of the contact reaction force causes the long
pinion and short pinion to be pushed against the differential case (cases A and B). This force generates
a large friction between the long pinion, short pinion, and differential case (cases A and B).
Friction also occurs on the gear with the generation of contact reaction force (F and f) of the four
gears (pinions).
These frictional forces cause the generation of frictional torque at each section according to the
size of the driving torque input to the differential case, and the generation of limited slip differential
torque proportionate to the input torque.
 POWER TRAIN - Manual Transmission 2-11

Driving power Forward direction

Thrust washer
Torque F Fr fr f

High speed Ft ft
side
Low speed
side

Long pinion

Thrust washer
Differential case Short pinion
Side gear A Side gear B

TRANSMISSION CONTROL
D The shift lever construction adopted the D The shift and select cable securing portions
spherical rotary shaft fulcrum type to assure have been elastically supported to reduce
a non-rickety. contained sound.
D The base bracket material adopted a synthetic D A mass-filled shift knob has been adopted to
resin for the weight reduction. minimize the binding touch at the time of a
shift.

CONSTRUCTION DIAGRAM

Select cable

Shift lever assembly

Shift cable

Base bracket
2-12 POWER TRAIN - ACD and AYC

ACTIVE CENTER DIFFERENTIAL (ACD) AND ACTIVE YAW

CONTROL (AYC)
The LANCER EVOLUTION-VII adopts the newly developed active center differential (ACD).
The driving performance of the ACD has been improved by varying the center differential drive by electronic
control.
The yaw moment is directly controlled by the active yaw control (AYC) adopted from EVOLUTION-V
onwards to improve the turning performance.
By combining and integratedly controlling these two systems, the driving performance has been further
improved.
RS, RS II
ACD Option
ACD and AYC Option

OUTLINE OF CONTROL
The following effects are obtained by equipping the ACD or ACD and AYC.
State of vehicle ACD AYC Integrated control effects
1. During de- Similar to the direct engagement [When decelerated during Stability against various
celeration 4WD by increasing the center turning] external influences such as
(Before differential during sharp decelera- The driving power is moved to poor road conditions and
corners) tion to improve stability in decelera- the inside turning wheel to driver operations have been
tion. reduce the tack in. improved.
2. First half of The center differential restriction is The driving power is moved to The response to steering
turning reduced according to the steering the outside turning wheel operations (brisk move-
(Corner en- angle and operation speed to set according to the steering ment) is improved as much
trance) the center differential as close as angle and operation speed to as possible.
possible to the free state and improve the turning perfor-
improve turning performance. mance.
3. Latter half The center differential restriction is The driving power is moved to Two elements (acceleration
of turning enhanced according to the amount the outside turning wheel and turning) have been
(Corner the acceleration is stepped to set according to the amount the improved simultaneously.
exit) similar effects as the direct engage- acceleration is stepped to
ment 4WD and improve the accel- decrease the acceleration
eration performance. understeer and improve turn-
ing performance.

2. First half of turning

3. Latter half of turning
AYC: Under steer deceleration
AYC: Turning

ACD: Direct engagement

ACD: Free

1. During deceleration
ACD: Direct
engagement
AYC: Tack in deceleration
(During deceleration when turning)
 POWER TRAIN - ACD and AYC 2-13
COMPONENT VIEW

ACD mode indicator lamp

AYC torque transfer

differential
Parking brake switch
Steering
wheel sensor

Throttle position sensor (TPS)

Reserve tank

ABS-ECU

Hydraulic unit
assembly
Lateral G sensor
Wheel speed sensor
Longitudinal
ACD transfer G sensor

Engine-ECU
ACD mode switch
4WD-ECU
Stop lamp switch

Wheel speed sensor

2-14 POWER TRAIN - ACD and AYC

LIST OF MAIN COMPONENTS

Components Outline of function

ACD transfer Controls the transmission torque of the hydraulic multi plate clutch by the
hydraulic unit, and adjusts the center differential.
4WD-ECU Processes information of various sensors and switches, calculates the hydraulic
multi plate clutch transmission torque and amount of AYC torque movement and
direction, and controls the hydraulic unit on the basis of them.
Engine-ECU Sends the engine idling state to the 4WD-ECU.
ABS-ECU Outputs the ABS monitor signal to the 4WD-ECU.
Throttle position sensor (TPS) Sends the throttle valve opening angle to the 4WD-ECU.
Longitudinal G sensor Sends the acceleration in the front and rear directions of the vehicle to the
4WD-ECU.
Lateral G sensor Sends the acceleration along the side of the vehicle to the 4WD-ECU.
Steering wheel sensor Sends the steering angle and neutral position to the 4WD-ECU.
Wheel speed sensor Sends the wheel speed to the 4WD-ECU.
Stop lamp switch Sends the brake operating state to the 4WD-ECU.
Parking brake switch Sends the operating state of the parking brake to the 4WD-ECU.
ACD mode indicator lamp
p Displays the ACD control mode (TARMAC, GRAVEL, SNOW).
Lights the all mode lamp during fail. (Lights for about 1.5 seconds after the ignition
switch is turned ON)
ACD mode switch Switches the ACD control mode (TARMAC, GRAVEL, SNOW).
Hydraulic
y Pressure sensor Sends the pressure of the accumulator to the 4WD-ECU.
unitit Electric pump Generates oil pressure for clutch operations.
Directional valve Controls whether to supply the oil pressure to the left or right AYC clutch.
Proportional valve Controls hydraulic supplied to hydraulic multi plate clutch of the ACD.
<ACD>
Proportional valve Controls oil pressure supplied to the AYC clutch.
<AYC>
Electric pump relay Supplies the power to the electric pump.
AYC torque transfer differential Controls the transmission torque of the left and right clutches according to the
oil pressure from the hydraulic unit, and adjusts the left and right driving power
difference of the rear wheels.
 POWER TRAIN - ACD and AYC 2-15
OUTLINE OF ACD AND AYC

Idling information
Engine-ECU
<ACD and AYC
Equipped Vehicle>
ACD mode switch
ABS monitor signal
Parking brake switch
Wheel speed sensor <FL>
ABS- Wheel speed sensor <RL> ACD mode indicator lamp
ECU Wheel speed sensor <RR>
Wheel speed sensor <FR>
Diagnostic connector

Wheel speed sensor <FL>*1

Wheel speed sensor <RL>*1 Direction valve*2
4WD-ECU
Wheel speed sensor <RR>*1
Wheel speed sensor <FR>*1 Proportional valve*2 (AYC)
Longitudinal G sensor
Lateral G sensor Proportional valve (ACD)
Stop lamp
Steering wheel sensor
Pressure sensor
Throttle position sensor
ECU power supply

Electric
pump
Steering wheel sensor

Stop lamp switch

Wheel speed Reservoir
sensor <FR> Wheel speed sensor <RR> tank relay

Pressure
sensor

Lateral G sensor
Longitudinal G sensor Right clutch*2
ACD transfer Proportional Accu-
Left clutch*2 valve mulator
(ACD)
Hydraulic
multi
Electric
plate clutch
Proportional pump
valve*2
(AYC)
Center
differential Directional
valve*2

Hydraulic unit
AYC torque transfer
differential *2
Wheel speed sensor <FL> Wheel speed sensor <RL>
NOTE
1. *1 indicates equipped with only ACD.
2. *2 indicates equipped with ACD and AYC.
2-16 POWER TRAIN - ACD and AYC

DESCRIPTION OF STRUCTURE AND OPERATIONS

The ACD system adopts a transfer limited slip differential as the hydraulic multi plate clutch, and electronically
controls it using sensors, 4WD-ECU, and hydraulic unit.
NOTE
Refer to P.2-30 for details on the AYC structure and operations.
SYSTEM STRUCTURE

AYC torque transfer

differential
ACD transfer

Hydraulic unit
(Electric pump with
accumulator)

Engine

4WD-ECU

T/M
Steering wheel sensor

TPS

Wheel speed sensor

Longitudinal G sensor

Lateral G sensor

Sensors
 POWER TRAIN - ACD and AYC 2-17
TRANSFER LIMITED SLIP DIFFERENTIAL
During acceleration and deceleration, the piston is moved in the right direction according to the oil pressure
from the hydraulic unit to connect the hydraulic multi plate clutch (friction plate and disc) and set the
center differential to the direct engagement state as much as possible. This improves the acceleration
performance and stability during deceleration.
During turning, the oil pressure from the hydraulic unit stops, the piston operates in the left direction
to release the hydraulic multi plate clutch and free the center differential to improve the turning performance.
If the parking brake is pulled while driving at a vehicle speed above 5 km/h, the hydraulic multi plate
clutch will also be released and the center differential set as close as possible to the free state.

Hydraulic unit
assembly

ACD transfer

Section A - A

Piston <During acceleration

and deceleration>
Thrust bearing

Transfer hydraulic case Hydraulic multi plate clutch

(Friction plate and disk)

<During turning>
2-18 POWER TRAIN - ACD and AYC

HYDRAULIC UNIT
The hydreaulic unit is composed of the accumulator (electric pump, pressure sensor, accumulator) and
pressure controller (proportional valve, directional valve).
The pressure accumulator intermittently operates the pump, and accumulates the control pressure required
in the accumulator.
The pressure controller operates the proportional valve and directional valve, and supplies the appropriate
oil pressure to the ACD transfer or AYC torque transfer differential according to the signals from the
4WD-ECU.
SPECIFICATIONS
Specifications Specifications
Electric pump Trochoidal type
Operating oil ATF SP III
Proportional valve Current proportional control type
Directional valve 3 position electromagnetic switching method

TPS

Stop lamp switch Hydraulic unit assembly

Wheel speed sensor Pressure sensor

Electric pump relay
Longitudinal G sensor
Electric Accu-
pump mulator
Lateral G sensor
4WD-ECU ACD transfer
Steering wheel sensor
Proportional Proportional
valve (AYC) valve (ACD) Hydraulic multi
Engine-ECU plate clutch
Directional
ABS-ECU valve

ACD mode switch

Parking brake switch

Electronic control system ACD mode

indicator lamp Left Right
Oil pressure control system
AYC clutch

Proportional valve
Supplies the oil pressure required for ACD or AYC control
according to the instructions of the 4WD-ECU.
Proportional
valve <ACD>

Proportional
valve <AYC>
 POWER TRAIN - ACD and AYC 2-19
When the proportional valve is OFF, the oil pressure from
Proportional
From electric pump the electric pump will be cut off by the proportional valve.
valve (OFF) For this reason, oil pressure will be supplied to the ACD
or AYC and each system will be set into the non-operating
state.

Proportional When the proportional valve turns ON, the proportional valve
From electric pump
valve (ON) opens, and the oil pressure from the electric pump will be
supplied to the ACD hydraulic multi plate clutch or AYC
directional valve.

Return

To ACD hydraulic multi plate

clutch or AYC directional valve

Directional valve
Supplies the oil pressure required for controlling the AYC
clutch according to the instructions of the 4WD-ECU.

Directional
valve

From proportional When the directional valve is OFF, the oil pressure from the
Directional valve <AYC> proportional valve <AYC> will be cut off by the directional
valve (OFF) valve. For this reason, the clutch will set into the non-operating
state without oil pressure supplied to each clutch of the AYC.

To clutch To clutch
<Left side> <Right side>

Directional valve From proportional valve When oil pressure supply signal for the AYC clutch <Right
(Right side: ON) <AYC> side> is sent to the directional valve from the 4WD-ECU,
the directional valve will move to the right. As a result, the
oil pressure from the proportional valve <AYC> will be supplied
to the AYC clutch <Right side>.
If the oil pressure supply signal to the AYC clutch <Left side>
is sent to the directional valve, the directional valve will move
to the left.
To clutch
<Left side> To clutch
<Right side>
2-20 POWER TRAIN - ACD and AYC

ELECTRONIC CONTROL SYSTEM

THROTTLE POSITION SENSOR
For detecting the throttle valve opening angle. Also used as throttle position sensor for engine control.

LONGITUDINAL G SENSOR/LATERAL G SENSOR

The longitudinal G sensor are sensors detecting the acceleration in the longitudinal directions of the
vehicle, and are basically the same as those used conventionally.
The lateral G sensor is used for detecting the acceleration along the sides of the vehicle by changing
the installing direction by 90° . The same sensor as the longitudinal G sensor is used.
G-sensor output characteristics
Parking brake lever
Output voltage (V)
Lateral G sensor
4.0
3.5

2.5
Longitudinal
G sensor 1.5
1.0

1.5 1.0 0 1.0 1.5

Acceleration speed Deceleration speed
(G) (G)

STEERING WHEEL SENSOR

The steering wheel sensor is installed at the steering column, and is used to output steer angles to
the 4WD-ECU as signals.
It is composed of the slit plate which rotates according to the movements of the handle and a three-set
photointerruptor. The slit plate and photointerruptor have a sealed integrated structure to prevent the
invasion of foreign particles as well as misoperations by external light. To detect malfunctions of the
sensor output circuit, it is equipped with a zener diode for detecting disconnections parallel to the
phototransistor.
The ECU calculates the steering angle by reading the signals of the steering wheel sensor after every
certain period of time and calculating the total of the ST-1 signal and ST-2 signal.
The steering angle is obtained by taking the neutral position (ST-N output is L center) as 0° , and if
there are changes, the steering angle is added with 2° for right and - 2° for left. The output of the
photointerruptor becomes L (low) when light passes through and H (high) when obstructed.
 POWER TRAIN - ACD and AYC 2-21
Output waveform of each sensor
N (Neutral point)
2°
Steering wheel sensor
V H
4° 4°
ST-1
L

V
H
4° 4°
ST-2
L

V H
Slit 11°
ST-N
L

Slit plate

Slit plate

Photointerruptor Neutral position

(ST-2) detection slit

Zener diode
for disconnec-
tion detection
Photointerruptor
(ST-N)
Photointerruptor
(ST-1)

Light-emitting diode Photo-transistor

<Front> WHEEL SPEED SENSOR

Sensor for detecting each wheel speed. It is the same as
that conventionally adopted for the ABS. For vehicle with
ACD and AYC, the wheel speed sensor signal
waveform-shaped by the ABS-ECU is input to the 4WD-ECU.

Wheel speed sensor

<Rear>
Wheel speed sensor
2-22 POWER TRAIN - ACD and AYC

ACD MODE SWITCH

When the ACD mode switch is pressed, the mode switches
to TARMAC, GRAVEL, or SNOW.
ACD mode TARMAC GRAVEL SNOW
Good condi- Dry paved Wet roads, Snowy roads
tion roads roads gravel roads

ACD mode switch

ACD MODE INDICATOR LAMP

ACD mode indicator lamp
For about 1.5 seconds after the Ignition switch is turned ON,
all ACD mode indicator lamps will light up. When the ACD
mode switch is pressed, each mode (TARMAC, GRAVEL,
SNOW) will light up alternately.
When the ACD or AYC malfunctions, all mode indicators will
light up (until the ignition switch goes OFF*).
NOTE
*: When the vehicle is determined as having returned to normal
according to the malfunction, the lamps will also be returned
to their normal states.
PRESSURE SENSOR
Detects the pressure of the accumulator, and sends the signal
Pressure to the 4WD-ECU. The 4WD-ECU controls the operations of
sensor
the electric pump on the basis of this signal.

Hydraulic unit
assembly

ELECTRIC PUMP RELAY

Supplies power to the electric pump according to the signal
from the 4WD-ECU.

Electric pump relay

4WD-ECU
4WD-ECU
Determines the driving state, vehicle state, and road state
according to the inputs of each sensor, idling information
from the engine-ECU, and ABS monitor signal from the
ABS-ECU to control the hydraulic unit.
The 4WD-ECU also has a diagnosis function which lights
up all the ACD mode indicator lamps during malfunctions.

Door check
 POWER TRAIN - ACD and AYC 2-23
The terminals of the 4WD-ECU are arranged as follows.

1. Proportional valve <ACD> 25. -

2. - 26. ECU earth
3. Proportional valve <AYC>*1 31. ECU backup power supply
4. - 32. Pressure sensor
5. - 33. Steering wheel sensor <ST-1>
6. Wheel speed sensor <FL> 34. Steering wheel sensor <ST-2>
7. Wheel speed sensor <RR> 35. Diagnosis data input/output
8. Wheel speed sensor <RL> 36. Idle switch
9. Wheel speed sensor <FR> 37. Parking brake switch
10. Pressure sensor earth 38. Stop lamp switch
11. Lateral G sensor 39. TPS
12. - 40. ACD mode indicator lamp <TARMAC>
13. 4WD-ECU power supply 41. -
14. Directional valve <Right>*1 42. ECU earth
15. Directional valve <Left>*1 43. Pressure sensor power supply
16. Electric pump relay power supply 44. Steering wheel sensor <ST-N>
17. - 45. -
18. - 46. Diagnostic control
19. Wheel speed sensor earth <FL>*2 47. ACD mode switch
20. Wheel speed sensor earth <RR>*2 48. -
21. Wheel speed sensor earth <RL>*2 49. ABS monitor *1
22. Wheel speed sensor earth <FR>*2 50. Earth*2
23. Longitudinal G sensor 51. ACD mode indicator lamp <SNOW>
24. Longitudinal G sensor and lateral 52. ACD mode indicator lamp <GRAVEL>
G sensor earth *2

NOTE
1. *1 indicates that the terminal is omitted if only ACD is equipped.
2. *2 indicates that the terminal is added if only ACD is equipped.

DIAGNOSIS ITEMS
Code Diagnosis Item Mode indica- Main diagnosis details
No. tor lamp (f: all
lit, – : normally
displayed)
12 Power supply voltage f Open-circuit, short-circuit of power supply voltage system, or
(Valve power supply) drop in voltage
13 Fail save relay f Open-circuit or short-circuit of ECU equipped fail save relay
21 Wheel speed sensor f Open-circuit or short-circuit of wheel speed sensor <FR>
<FR> system
22 Wheel speed sensor <FL> f Open-circuit or short-circuit of wheel speed sensor <FL>
system
23 Wheel speed sensor f Open-circuit or short-circuit of wheel speed sensor <RR>
<RR> system
24 Wheel speed sensor f Open-circuit or short-circuit of wheel speed sensor <RL>
<RL> system
25 Wheel speed
p sensor - Equipped with step-bore tire
26 f Wheel speed sensor defect
31 Steering wheel sensor f Steering wheel sensor <ST-N,ST-1,ST-2> system
opened or short-circuit
2-24 POWER TRAIN - ACD and AYC

Code Diagnosis Item Mode indica- Main diagnosis details

No. tor lamp (f: all
lit, – : normally
displayed)
32 Steering
g wheel sensor f Steering wheel sensor <ST-N> system short-circuit
33 <ST-N>
ST N f Fixing of steering wheel sensor <ST-N> system
34 Steering wheel sensor f Short-circuit or fixing of output of steering wheel sensor <ST-1,
<ST-1, ST-2> ST-2> system
41 TPS f Open-circuit or grounding of TPS system
42 f Short-circuit of TPS system
45 Pressure sensor f Open-circuit or short-circuit of pressure sensor system
46 f Earth open-circuit of pressure sensor system
47 f Power supply defect of pressure sensor system
51 Longitudinal
g G sensor f Open-circuit and short-circuit of longitudinal G sensor system
52 f Longitudinal G sensor defect
56 Lateral G sensor f Open-circuit or short-circuit of lateral G sensor
57 f Lateral G sensor defect
61 Stop lamp switch f Open circuit of stop lamp switch system
62 ACD mode switch f ACD mode switch is stuck
63 Parking brake switch f Short-circuit of parking brake switch or it has not been returned
to designated position
65 ABS f Open-circuit of ABS monitor system or malfunction of ABS
71 Proportional valve <AYC> f Open-circuit or short-circuit of proportional valve <AYC>
system
72 Directional valve <Right> f Open-circuit or short-circuit of directional valve <right> system
73 Directional valve <Left> f Open-circuit or short-circuit of directional valve <left> system
74 Proportional valve <ACD> f Open-circuit or short-circuit of proportional valve <ACD>
system
81 Electric pump
p p relayy f Open-circuit or short-circuit of electric pump relay system
82 f Electric pump malfunction or pressure sensor defect
84 AYC control f AYC control defect
85 ACD control f ACD control defect
 POWER TRAIN - ACD and AYC 2-25
SERVICE DATA
Item No. Item Unit
01 Wheel speed sensor <FR> km/h (Displayed for every 1 km/h)
02 Wheel speed sensor <FL> km/h (Displayed for every 1 km/h)
03 Wheel speed sensor <RR> km/h (Displayed for every 1 km/h)
04 Wheel speed sensor <RL> km/h (Displayed for every 1 km/h)
05 Wheel speed sensor <FR> (0.2 km/h) km/h (Displayed for every 0.2 km/h)
06 Wheel speed sensor <FL> (0.2 km/h) km/h (Displayed for every 0.2 km/h)
07 Wheel speed sensor <RR> (0.2 km/h) km/h (Displayed for every 0.2 km/h)
08 Wheel speed sensor <RL> (0.2 km/h) km/h (Displayed for every 0.2 km/h)
09 Vehicle speed km/h
10 Battery voltage V
11 Proportional valve current<ACD> mA
12 Proportional valve current <AYC> mA
13 TPS voltage mV
14 Longitudinal G sensor voltage V
15 Lateral G sensor voltage V
16 Steering angle deg
17 Steering angle speed deg/s
18 Pressure sensor MPa
19 Pressure sensor power supply V
20 Valve power supply V
21 Steering wheel sensor voltage <ST-1> V
22 Steering wheel sensor voltage <ST-2> V
23 Steering wheel sensor voltage <ST-N> V
51 Idle switch ON/OFF
52 Steering wheel sensor <ST-N> ON/OFF
53 Steering wheel sensor <ST-1> ON/OFF
54 Steering wheel sensor <ST-2> ON/OFF
55 Steering wheel sensor learning <ST-N> ON/OFF
56 Stop lamp switch ON/OFF
57 Motor monitor ON/OFF
58 Oil pressure state HIGH/LOW
59 Directional valve <Right> ON/OFF
60 Directional valve <Left> ON/OFF
61 ABS monitor ON/OFF
62 Parking brake switch ON/OFF
63 ACD mode switch ON/OFF
2-26 POWER TRAIN - ACD and AYC

ACTUATOR TEST
Item No. Content Drive Specifications Driving Check
time
01 Bleeding Outputs current to the 5 minutes Check that no air is discharged from the
<ACD> proportional valve accord- bleeder screw installed on the ACD
ing to the steering angle. transfer.
02 Bleeding Outputs current to the 5 minutes Check that no air is discharged from the
<AYC> proportional valve accord- bleeder screw installed on the AYC torque
ing to the steering angle to transfer differential.
operate the direction
valve.
03 Oil amount Operates the directional 20 sec- Check the oil amount of the reservoir tank.
check valve to the left and right. onds
04 Electric pump Operates the electric To end of Check the operating state from the
drive pump for 5 seconds. operations operation sound of the electric pump.
05 ACD clutch op- Operates the proportional 1 minute With the vehicle lifted up, check the
eration check valve <ACD> to supply operating state according to the speed
maximum oil pressure to difference between the front and rear
the multi plate clutch. wheels.
06 AYC clutch op- Operates the directional 1 minute With the vehicle lifted up, check the
eration check valve, and supplies maxi- operating state according to the speed
<Left side> mum oil pressure to the difference between the front and rear
left side clutch. wheels.
07 AYC clutch op- Operates the directional 1 minute With the vehicle lifted up, check the
eration check valve, and supplies maxi- operating state from the speed difference
<Right side> mum oil pressure to the between the left and right rear wheels.
right side clutch.
08 Control OFF Turns OFF the electric - Check the difference between control ON
pump relay, and ACD and OFF in actual driving.
control and AYC control.
 POWER TRAIN - Propeller Shaft 2-27
PROPELLER SHAFT
3 way split 4-joint type propeller shaft with center bearing is adopted.
SPECIFICATIONS
Item Vehicles without AYC Vehicles with AYC

Propeller Type 3 way split 4-joint type propeller shaft

shaft
Length × Outside Front 608.5 × 65
diameter mm
Center 551 × 65

Rear 750.5 × 65 768.5 × 65

Universal Type No.1 Cross type (caulking method)

joint
No.2 Cross type (caulking method)

No.3 Constant velocity type (LJ)

No.4 Cross type (caulking method)

Bearing Lubricationless type needle roller bearing

Journal diameter mm 16.3

NOTE
The propeller shaft length indicates the length between the centre points of each joint.
CONSTRUCTION DIAGRAM

Center bearing Rear propeller shaft

No.2 joint
Front propeller shaft

Sleeve yoke

No.4 joint
No.3 joint
(LJ)
Center propeller shaft

No.1 joint
2-28 DRIVETRAIN - Front Axle

FRONT AXLE
The front axle consists of front hubs, knuckles, D The drive shaft incorporates B.J.-T.J. type
wheel bearings and drive shafts, and it has the constant velocity joints with high transmission
following features. efficiency and low vibration and noise.
D The wheel bearing is unit bearing (Double-row D ABS rotors for detecting the wheel speeds are
angular contact ball bearing) which is integrated press-fitted to the B.J. outer wheels in vehicles
with hub. with ACD or ABS.

NOTE
1. B.J.: Birfield Joint
2. T.J.: Tripod Joint
SPECIFICATIONS
Item Specifications
Wheel Wheel bearing type Hub unit bearing (Double-row angular
g
bearings contact ball bearing)
Bearing (outside diameter) mm 87*1
Drive Joint type Outside B.J.
shaft
Inside T.J.
Shaft length*2 × Shaft diameter mm Left 350 × 26
Right 427 × 26

NOTE
*1: The wheel bearing is integrated with hub,only the outer diameter is shown.
*2: The shaft length indicates the length between the center points of each joint.
STRUCTURAL DIAGRAM

Strut assembly Output shaft

T.J.(L.H.)

Knuckle

Front hub T.J.

Drive shaft
T.J.(R.H.)

B.J. Output shaft

Wheel bearing
 DRIVETRAIN - Rear Axle 2-29
REAR AXLE
The rear axle consists of rear hubs, wheel bearings, D The drive shaft incorporates B.J.-T.J. type
drive shafts, and rear differentialand, it has the constant velocity joints with high transmission
following features. efficiency and low vibration and noise.
D The wheel bearing is a unit bearing (double-row D ABS rotors for detecting the wheel speeds are
angular contact ball bearing). press-fitted to the B.J. outer wheels in vehicles
with ACD or ABS.

NOTE
1. B.J.: Birfield Joint
2. T.J.: Tripod Joint
SPECIFICATIONS
Item Vehicles without AYC Vehicles with AYC
Wheel Wheel bearing type Unit bearing (Double-row angular contact ball
g
bearings bearing)
Bearing (outside diameter × inside diameter) mm 78 × 40
Drive Joint type Outside B.J.
shaft
Inside T.J.
Shaft length*1 × Shaft diameter Left 483 × 25 426 × 25
mm
Right 573 × 25 446 × 25

NOTE
*1: The shaft length indicates the length between the center points of each joint.
STRUCTURAL DIAGRAM

Differential carrier
T.J.
B.J.
Oil seal Rear hub

Drive shaft
2-30 DRIVETRAIN - Differential

DIFFERENTIAL
Mechanical type Limited Slip Differential <Vehicles without AYC> or Torque transfer differential <Vehicles
with AYC> is adopted. About the structure of AYC, refer to P.2-3, manual transmission.
MECHANICAL LIMITED SLIP DIFFERENTIAL
SPECIFICATIONS
Item Mechanical LSD
Reduction gear type Hypoid gear
Reduction ratio 3.312
Differential g
gear type
yp ((Type
yp × Side gear Straight bevel gear × 2
number
b off gears)) Pinion gear Straight bevel gear × 4
Number of teeth Drive gear 43
Drive pinion 13
Side gear 14
Pinion gear 10
Bearings
g (Outside
( diameter × Side 72.0 × 35.0
I id diameter)
Inside di t ) mm Front 62.0 × 25.0
Rear 72.0 × 35.0

CONSTRUCTION DIAGRAM
<Mechanical LSD>

Differential carrier
 DRIVETRAIN - Differential 2-31
TORQUE TRANSFER DIFFERENTIAL
The torque transfer differential consists of differential mechanism,acceleration/decelation gear and two
pairs of wet multi-plate clutch. The hipoid gear oil is used to lublicate differential part, ATF-SP III is used
to lublicate torque movement part (acceleration/decelation gear and clutch).

L.H. clutch
Differential Wet multi-plate clutch
mechanism R.H. clutch

Reductiongear
Input gear Overdrive gear

Acceleration/decelation gear

DIFFERENTIAL MECHANISM
When the vehicle turns, admits the revolution difference between inner race and outer race.
ACCELERATION/DECELATION GEAR
Have the revolution speed of right and left wet multi-plate clutch to accelerate or decelate as oposed
to the revolution speed of right wheel.
WET MULTI-PLATE CLUTCH
Have the torque to move from high speed wheel to low speed wheel.
L.H. clutch operate: decelation geer have the torque to move R.H. wheel to L.H. wheel.
R.H. clutch operate: accelelation geer have the torque to move L.H. wheel to R.H. wheel.
The movement of torque is dependence on pushing force of the clutch.
2-32 DRIVETRAIN - Differential

TORQUE TRANSFER DIFFERENTIAL MECHANISM

High Low
speed speed When high speed clutch is pushed, the driving power always
side side moves from high speed side to low speed side, and controls
the driving power with the aid of the property which the
movement of driving power is proportional to the pushing
Pushing Pushing force of clutch.
force force In torque transfer differential, acceleration/decelation gear
always engages, and towerd to input speed from the
Driving differential case, L.H. clutch engaging decelation gear is
power
moves revolutes in low speed, R.H. clutch engaging accelelation
gear is revolutes in high speed.
In the other hand, the housing side of R.H/L.H. clutch is
Differential L.H. R.H. integlated to rear R.H. axle, if R.H. or L.H. clutch is opelated,
case Clutch Clutch the driving power can be moved to right or left.

Decelation
gear Acceleration
gear

Turning Yaw THE FLOW OF DRIVING POWER

direction moment L.H.clutch (1) L.H.CLUTCH OPERATE
In order to boost the driving power of L.H. wheel, when
L.H.clutch is operated,a part of the driving power of R.H.
Driving Driving
power power wheel flows to the differential case, the driving power
(large) (small) of L.H. wheel is boosted.
The result of this, the yaw moment occures in a right
to the vehicle.

Yaw Turning (2) R.H.CLUTCH OPERATE

moment direction In order to boost the driving power of R.H. wheel,when
R.H.
clutch
R.H.clutch is operated, a part of the driving power of
L.H. wheel flows to the differential case, the driving power
Driving
Driving of R.H. wheel is boosted.
power The result of this, the yaw moment occures in a left to
power (large)
(small) the vehicle.
 DRIVETRAIN - Differential Mount 2-33
DIFFERENTIAL MOUNT
The front of differential carrier is suported with the The front of torque transfer differential is supported
differential support member via the differential with the differential support member with insulator
mount bracket with insulator,and the rear is via the differential mount bracket,and the rear is
suported with the differential support arm. supported with the differential mount bracket and
<Mechanical LSD> the differential support arm. <AYC>
<Mechanical LSD>
Toe control bar

Differential support member

Differential support arm

Differential mount bracket

Insulator

<AYC> Differential support arm

Differential support member

Differential mount bracket

Differential mount
bracket (R.H.)

Insulator

Differential mount
bracket (L.H.)
NOTES