Land Rover Lesson 2 Auto Trans Coolingine Rover Manual

							High range actuation sequence
Shifting sleeve1
High/low shifting fork2
Shifting cam3
The rotational movement of the motor shaft turns the
shifting cam (3) to high range position. The shifting
cam then moves the shifting sleeve (1), via the high/low
shifting fork (2), into the high range position. After the
synchronisation sequence, the planetary ring gear is
connected to the high range dogteeth, via the shifting
sleeve, on the differential carrier. In this position, the
input speed equals the output speed, which equates to
a high range ratio of 1:1.
Low range actuation sequence
Shifting sleeve1
High/low shifting fork2
Shifting cam3
Motor shaft4
The rotational movement of the motor shaft (4) turns
the shifting cam (3) into low range position. The shifting
cam then moves the shifting sleeve (1) of the centre
differential assembly via the high/low shifting fork (2)
into low range position. After the synchronisation
sequence, the planetary ring gear is connected to the
low range dogteeth, via the shifting sleeve, on the rear
carrier assembly. The output speed is then reduced to a
ratio of 2.93:1.
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							MULTI-PLATE CLUTCH ASSEMBLY
Clutch hub1
Cup springs2
Clutch plates3
Clutch piston4
Motor levers5
Ball ramp mechanism6
Sprocket7
The multi-plate clutch assembly for both centre and rear
differentials act in a similar way. The aim of the
multi-plate clutch assembly is to prevent excessive
differential slip and therefore maximise the traction
performance of the vehicle. This is fundamentally
different from the braked traction control, which can
only counter act differential slip when it occurs.
A certain amount of differential slip is required to allow
the vehicle to turn corners and to remain stable under
control of the Anti-lock Braking System (ABS). The
transfer box control module monitors the drivers
demands through primary vehicle controls and
automatically sets the slip torque at the differentials.
The system is completely automatic and does not require
any special driver input.
The multi-plate clutch assembly actively controls the
torque flow through the centre differential and optimises
the torque distribution in the driveline. The clutch
assembly biases the torque from the transmission to the
axle and wheels with the higher grip and prevents the
wheels with the lower grip from spinning.
The multi-plate clutch assembly comprises the sprocket
(7), which is connected to the front differential side gear,
the motor levers (5) with the ball ramp mechanism (6),
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							the clutch hub (1) as support for the clutch plates (3),
the clutch piston (4) to generate friction between the
clutch plates, and a pack of cup springs (2) to return the
clutch piston into its original position.
One set of friction plates are connected to the clutch
hub; the other set of friction plates are connected to the
multi-plate clutch basket, which is welded to the centre
differential housing.
Multi-plate Clutch Actuation
Transfer box motor levers in initial position, multi-plate clutch open condition
Transfer box motor in end position, multi-plate clutch closed condition
Clutch piston1
Motor shaft2
Clutch control disc3
Motor levers4
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							Ramp mechanism balls5
By turning the clutch control disc (3), via the motor
shaft (2), the motor levers (4) are rotated relative to each
other. This relative movement acts on 5 balls (5) in a
ramp mechanism between the two levers and give a
defined axial movement. The movement forces the
clutch piston (1) to induce friction between the plates
supported by the clutch hub and the plates supported by
the clutch basket on the differential carrier. This
frictional force inhibits the differential rotation; the
differential carrier and front differential side gear are
locked together.
TRANSFER BOX CONTROL
MODULE
The transfer box control module controls the high/low
shift-on-the-move actuation and the multi-plate clutch
actuation. The control module is located in the E-box,
next to the Engine Control Module (ECM), behind the
battery in the engine compartment. The position of the
control module changes with LH and RH drive vehicles.
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							RH driveA
LH driveB
Battery Junction Box (BJB)1
Battery2
Engine Control Module (ECM)3
Transfer box control module4
The control module is connected to the Controller Area
Network (CAN) bus and controls the transfer box
operation using CAN messages from other control
modules on the network.
The control module memorises the position of the
transfer box motor when the ignition is switched off.
The transfer box control module uses the same actuator
to control both range change function and application
of centre differential locking torque. The module uses
position feed back from the actuator to provide smooth
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							range changing capability and graduated application of
locking torque appropriate for the current driving
conditions. Range change can be carried out while
moving providing the transmission is in neutral and the
vehicle is below the speed necessary for the requested
range change.
The control module uses three connectors for all inputs
and outputs. It receives a permanent power supply via
a 30A fusible link located in the Battery Junction Box
(BJB), and an ignition supply via fuse 24 in the Central
Junction Box (CJB).
The control module uses a series of programmed shift
maps to control the synchronisation speed and ensure
that a maximum shift time of approximately one second
is achieved.
If the control module is replaced, T4 must be connected
to the vehicle and the transfer box control module
self-calibration procedure must be performed. This
procedure must also be performed if the transfer box
motor assembly is replaced.
Default/Limp-home Strategy
If a fault occurs with the transfer box, the transfer box
control module or one of the required input signals i.e.
road speed signal, the control module records an error
code and will respond appropriately to provide the
highest level of system capability under the specific
fault conditions. The following fault states are possible:
Driver warningSystem responseFault state
NonDiagnostic Trouble Code (DTC) will
be recorded but no effect on
performance
No reduction in capability
Driveline over temperature warning
lamp or Centre diff over temp
reduce speed on message centre
The tractive capability of the vehicle,
off road, is reduced.
Clutch control not possible.
Temporary over temperature condi-
tion
Driveline fault warning lamp or
Centre diff fault traction reduced
on message centre
The tractive capability of the vehicle,
off road, is reduced.
Clutch control not possible.
Permanent fault
Driveline fault warning lamp or
Range change inoperable on
message centre
The system inhibits the driver from
making a range change
Range change not possible
Flash low range indicator plus Park
lock failure apply hand/parkbrake
message on message centre
The transfer box is stuck between
high and low range resulting in no
drive to wheels
Stuck in Transfer box neutral
If a driveline over temperature condition has occurred,
after the driveline has been allowed to cool, clutch
control will be re-enabled and the warnings will
disappear. There is no need to seek service assistance
following an over temperature event.
If clutch control or Range change is not possible due to
a permanent fault the driver must seek service assistance
at the earliest opportunity.
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							If the system suffers a fault, which causes the transfer
box to fail in neutral, the control module is designed to
continue attempting to engage the requested range or
return to its original range for a fixed number of
attempts. If this has not been successful and the low
range lamp is still flashing the driver should bring the
vehicle to a halt and attempt the range change again
while stationary. If this does not work after a number
of attempts, key off for 30 seconds, restart engine and
request range change again while stationary. The driver
must seek service assistance at the earliest opportunity.
Transfer Box Control Module Pin Out Details
Connector C1319
Input/outputDescriptionPin No.
-Not used1
-Not used2
Data (input and output)CAN bus low3
InputRange change selection switch - High4
InputRange change selection switch - Low5
Data (input and output)CAN bus high6
OutputKey interlock solenoid7
OutputLED-high8
OutputLED-low9
Connector C1854
Input/outputDescriptionPin No.
Data (input and output)CAN bus low1
-Not used2
InputIgnition power supply3
Data (input and output)CAN bus high4
-Ground5
InputPermanent battery power supply6
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							Connector C1855
Input/outputDescriptionPin No.
InputHall sensor signal-A1
-Ground2
OutputHall sensors supply3
-Not used4
InputTemperature sensor5
InputHall sensor signal-B6
-Selector position ground7
Output5V position sensor supply8
-Selector mode solenoid ground9
InputSelector position sensor signal10
InputTransmission position sensor X axis signal11
OutputSelector mode solenoid power supply12
InputTransmission position sensor Y axis signal13
OutputManual transmission output shaft speed sensor
supply
14
Input/outputMotor supply/ground15
InputManual transmission output shaft speed signal16
-Manual transmission output shaft speed sensor
ground
17
Input/outputMotor supply/ground18
TRANSFER BOX CONTROL
MODULE INPUTS
The transfer box control module receives the following
inputs:
•Range change selection switch
•High/low position sensor
•Transfer box actuator motor temperature
•Transfer box actuator motor position sensor
•CAN bus messages
•Gear position sensor (manual transmission only)
•Transmission output shaft speed sensor (manual
transmission only).
CAN Bus Messages
The CAN bus is a high speed broadcast network
connected between various vehicle control modules.
The CAN network carries an extensive list of messages
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							between the different control modules enabling more
sophisticated control with reduced complexity. Data on
the network is packaged for efficient communication
and prioritised according the urgency and importance
of the Messages. The bus comprises two wires, which
are twisted together to minimise electromagnetic
interference (noise) produced by the CAN messages.
The transfer box control module is connected on the
CAN bus and controls transfer box operation using CAN
messages from other control units on the network. Wheel
speed, vehicle acceleration, engine torque and speed,
gear information, from the automatic transmission,
temperature information, car configuration, axle ratios
and Terrain Response™ mode inputs, are some of the
main signals received by the control module.
In the event of a CAN bus failure the following
symptoms may be observed:
•Shift from high to low or low to high inoperative
•Instrument cluster low range warning lamp
inoperative
•warning messages or lamps displayed in instrument
cluster.
Gear Position Sensor (Manual Transmission Only)
The transfer box control module uses positional
information from the manual gear position sensor to
determine which gear the transmission is in. This
information is broadcast on the CAN bus for display on
the instrument cluster and for use by other vehicle
systems. Vehicles fitted with automatic transmission
use a similar message broadcast by the Transmission
Control Module (TCM). Vehicles fitted with manual
transmission have a learning function, which compares
the positional information from the sensor with the gear
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							ratio calculated from the ratio of engine speed to
transmission output shaft speed. The transmission
learning is carried out at end of manufacture. If a new
transmission is fitted during the life of the vehicle the
learning algorithm needs to learn the characteristics of
the new transmission.
The instrument cluster displays the selected gear as
determined by the transfer box. The transfer box also
uses this to check the vehicle is in neutral before
attempting a range change.
Manual Transmission Output Shaft Speed Sensor
The output shaft speed sensor is located at the rear of
the transmission and measures the speed of the
transmission output shaft.
The transfer box is designed to allow range changes
when the vehicle is moving, providing the transmission
speed complies with the preset thresholds determined
by the control module. The control module calculates
the optimised synchronization timing through the speed
of the transmission output shaft and the wheel speed of
the vehicle.
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