2002 MAZDA 6 wheel

OUTLINE
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4WD
Bold frames:New specifications
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ItemSpecification
New Mazda6 (GY)(Wagon 4WD)
EngineL3
TransaxleATX
Front axle Bearing type Angular ball bearing
Rear axle Bearing type Angular ball bearing
Front drive shaftJoint typeWheel side Bell joint
Differential side Tripod joint (With free ring)
Shaft diameter (mm {in}) 24.0 {0.94}
Joint shaft Shaft diameter (mm {in}) 29.0 {1.14}
Rear drive shaftJoint typeWheel side Bell joint
Differential side Double offset joint
Shaft diameter (mm {in}) 22.0 {0.87}
Rear and front wheel torque distribution unit Electronic control coupling
Rear differentialReduction gear Hypoid gear
Differential gear Straight bevel gear
Ring gear size (Inches) 6.5
Final gear ratio 2.928
Gears:
Number of teethDrive pinion 14
Ring gear 41
Differential oilTypeGrade API service GL-5
ViscosityAbove –18°C {0°F}: SAE 90
Below –18°C {0°F}: SAE 80
Amount
(Approximate quantity)(L {US qt, lmp qt}) 1.0 {1.1, 0.9}

DRIVE SHAFT
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DRIVE SHAFT OUTLINEA6E631625500201Features
Improved drivability, reduced noise and vibration
•Concurrent with the MZR-CD (RF Turbo) engine and 4WD system, the configuration of the front drive shaft and
the joint shaft has been optimized.
•For 4WD models, a constant velocity joint system has been adopted for the rear drive shaft.
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STRUCTURAL VIEWA6E631625500202
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REAR DRIVE SHAFTA6E631625500203Structure
•Engine noise and vibration have been reduced due to adoption of a bell joint on the wheel side of the constant
velocity joint.
•A low noise and vibration double offset joint with low slide resistance has been adopted for the differential side
of the constant velocity joint. Due to this booming resonance at high speed is reduced.
•An extremely durable plastic has been adopted for the wheel side boot.
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DRIVE SHAFT
3
1
2
A6E63162101
1 Front drive shaft
2 Joint shaft3 Rear drive shaft
5
4
31
2
A6E63162102
1 Wheel side
2 Bell joint
3 Differential side4 Double offset joint
5 Plastic boot

ELECTRONIC 4WD CONTROL SYSTEM
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OUTLINEA6E632227100201Features
Improved off-road mobility, handling stability, operability, fuel economy and marketability
•An electronic 4WD control system, which automatically optimizes traction distribution to the front and rear
wheels, has been adopted.
Improved serviceability
•A self-diagnostic function has been adopted for the electronic 4WD control system.
Electronic 4WD control system outline
•The newly adopted electronic 4WD control system automatically and optimally controls drive torque distribution
for the front and rear wheels. Due to this off-road mobility, driving stability and fuel economy are improved.
•Based on the input signals from each sensor, the 4WD control modure (4WD CM) determines vehicle driving
and road conditions, and controls output current to the electronic control coupling (4WD solenoid) inside the
rear differential. This control allows for optimal distribution of the drive torque from the engine to the rear
wheels.
•Also, the 4WD CM automatically controls the 4WD, greatly reducing the load on the driver and improving
operability.
Structural view
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ELECTRONIC 4WD CONTROL SYSTEM
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A6E63222001
1L.H.D.
2 R.H.D.
3 4WD warning light
4 4WD control modure
5 DSC HU/CM6PCM
7TCM
8 Electronic control coupling (4WD solenoid)
9 Differential oil temperature sensor
10 Rear differential

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ELECTRONIC 4WD CONTROL SYSTEM
Components and Functions
System Diagram
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Part name Function
Electronic control coupling
(4WD solenoid)•Based on a signal from the 4WD CM, it operates the electromagnetic clutch and
transmits drive torque to the rear wheels.
Differential oil temperature
sensor•Informs the 4WD CM of the rear differential oil temperature.
4WD CM•Controls operation of the electronic control coupling (4WD solenoid) based on signals
input from the throttle opening angle, speed, differential oil temperature and other
sensors.
•Outputs coupling control condition and 4WD warning control information as a CAN
signal.
•Controls the on-board diagnostic system and the fail-safe system if there is a malfunction
in the 4WD system.
4WD warning light•Illuminates or flashes to alert driver of a malfunction or control failure in the 4WD system.
PCM•Sends the throttle opening angle and engine speed signals, as CAN signals, to the 4WD
CM.
TCM•Sends the selector lever position and gear position signals, as CAN signals, to the 4WD
CM.
DSC HU/CM•Sends the four-wheel speed and DSC operating condition signals, as CAN signals, to the
4WD CM.
•Sends the coupling torque request signal, as a CAN signal, to the 4WD CM.
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C
NH G
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A6E63222002
1 Battery
2 Ignition switch
3 Differential oil temperature sensor
4 4WD control modure (4WD CM)
5 Electronic control coupling
6 4WD solenoid
7 Instrument cluster8 DSC HU/CM
9TCM
10 PCM
11 CAN-H
12 CAN-L
13 CAN driver

ELECTRONIC 4WD CONTROL SYSTEM
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End Of SieELECTRONIC CONTROL COUPLINGA6E632227100202Outline
Features
•An electromagnetic clutch, which operates smoothly due to the lack influence from the front and rear wheel
traction force, has been adopted for the electronic control coupling system.
•The construction of the coupling enables the torque formed by the pilot clutch to be amplified by the cam
mechanism, thus allowing the main clutch to obtain a high degree of torque. Due to this, size and weight
reduction of the component parts has been achieved.
Construction
•The electronic control coupling basically consists of an electromagnetic clutch, a cam mechanism and a torque
transmission system.
•The electromagnetic clutch consists of a 4WD solenoid (electromagnetic coil), rear-housing that forms a
magnetic path, pilot clutch, and armature. The cam mechanism consists of a pilot cam, balls, and main cam.
The torque transmission system consists of a main clutch and hydraulic oil (ATF).
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9
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1112
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A6E63222003
1 Front wheel side
2 Rear wheel side
3 Torque transmission system
4 Electromagnetic clutch
5 Rear housing
6 4WD solenoid (Electromagnetic coil)
7 Cam mechanism8Ball
9 Main clutch
10 Main cam
11 Armature
12 Pilot clutch
13 Pilot cam

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ELECTRONIC 4WD CONTROL SYSTEM
Operation
4WD solenoid control current is OFF
•When the 4WD solenoid control current is OFF, no torque is generated in the pilot clutch because there is no
current flowing to the 4WD solenoid. At the same time, the pilot cam and the main cam rotate in the same
direction via the balls, and the main cam does not exert any push force on the main clutch side. Therefore, the
traction from the front wheels is not transmitted to the rear wheels.
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8
7
5
4
3
6
12
56
7
A6E63222004
1 Main clutch
2 Pilot clutch
3 4WD solenoid (Electromagnetic coil)
4 4WD control modure (4WD CM)5Main cam
6Pilot cam
7Ball
8 Armature

ELECTRONIC 4WD CONTROL SYSTEM
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4WD solenoid control current is ON
•When the 4WD solenoid control current is ON, current flows from the 4WD CM to the 4WD solenoid, and the
coupling operates in the following manner.
1. Magnetic flux forms at the electromagnetic coil of the 4WD solenoid.
2. Due to the magnetic flux in the armature, the pilot clutch is suctioned towards the magnetic coil side and
made to engage. This causes frictional torque to generate in the pilot clutch.
3. The torque is transmitted to the pilot cam, which is engaged with the pilot clutch.
4. A rotational difference is created between the pilot cam and the main cam. Due to this relative torsion, the
cam mechanism operates, transmitting torque from the pilot cam to the ball and then to the main cam. In
this way, the push force exerted on the main clutch is amplified.
5. As the main clutch engages, the drive torque from the front wheels is transmitted to the rear wheels.
•The amount of push force exerted on the main clutch by the main cam (that is, the strength of the drive torque
transmitted to the rear wheels) changes in accordance with the proportion of the force acting upon the pilot
cam, engaged with the pilot clutch. Therefore, by changing the periodicity of the electric current from the 4WD
CM to the 4WD solenoid (ON/OFF rate of the 4WD solenoid = force acting on the pilot cam), the module
controls the transmission of drive torque to the rear wheels.
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3
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11
6
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56
7
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A6E63222005
1 Main clutch
2Pilot clutch
3 4WD solenoid (Electromagnetic coil)
4 4WD control modure (4WD CM)
5Main cam
6Pilot cam7Ball
8Armature
9 Drive torque
10 Magnetic flux
11 Input
12 Output

ELECTRONIC 4WD CONTROL SYSTEM
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4WD CONTROL MODUREA6E632227100205Function
•The 4WD control modure (4WD CM) calculates the optimal amount of torque distribution for the rear wheels
and outputs a corresponding electric current to the electronic control coupling (4WD solenoid). This calculation
is based on the throttle angle, four-wheel speed, engine speed, selector lever position, and other related input
signals, matched with the vehicle driving and road surface conditions.
Functions
Construction
•The 4WD CM is installed to the left of the brake pedal (clutch pedal position).
Block diagram
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Function name Contents
4WD system control
function•Based on each input signal, the electronic control current sent to the electronic control coupling
(4WD solenoid) is optimally controlled.
Diagnostic system•If the self-diagnostic system detects a malfunction, the 4WD warning light illuminates to alert
the driver, and at the same time the system suspends control or performs other measures to
prevent a loss of driving stability and protect the system.
•The detected malfunction is stored as a DTC in the 4WD CM.
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A6E63222008
1Front
2PCM
3TCM
4 DSC HU/CM
5 4WD control modure (4WD CM)
6 4WD solenoid
7Transaxle
8Transfer
9 Propeller shaft
10 Front drive shaft11 Pilot clutch/pilot cam
12 Ball/main cam
13 Main clutch
14 Electronic control coupling
15 Rear differential
16 Rear drive shaft
17 Torque transmission path
18 Electric signal path
19 Solenoid activation