Land Rover Anti Lock Control Traction Control Rover Manual

							Battery1
Fusible link 11E, BJB2
Fusible link 8E, BJB3
Air suspension ECU4
Diagnostic socket5
Instrument cluster6
Integrated head unit7
Parking brake module8
Automatic Temperature Control Module
(ATCM)
9
Tire Pressure Monitoring Module (TPMM)10
Park Distance Control Module (PDCM)11
Central Junction Box (CJB)12
Transfer box control module13
Engine Control Module (ECM)14
Rear differential control module15
ABS control module16
Transmission Control Module (TCM)17
Clutch pedal position sensor18
Restraints control module19
Parking brake switch20
Fuse 41P, CJB (ignition)21
Ignition switch22
Fuse 40P, CJB (key-in)23
Parking BrakeLesson 2 – Chassis
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							GENERAL
Electronic rear differentialA
Open rear differentialB
Rear driveshaft1
Electronic rear differential2
RH rear drive halfshaft3
Actuator (locking) motor assembly4
LH rear drive halfshaft5
Rear differential6
The open rear differential converts the angle of drive
through 90° and distributes drive, via the rear drive
halfshafts, to the rear wheels.
(G421061) Technical Training88
Lesson 2 – ChassisRear Drive Axle and Differential 
						

							The open rear differential for the V6 and V8 petrol
variants has the same output ratio, but the output ratios
for the TdV6 diesel are different, depending on whether
automatic or manual transmission is fitted.
The open rear differential is located centrally in the rear
of the chassis.
The units are mounted to the chassis via rubber bushes
and bolts; two mounting points at the rear of the unit
and one at the front.
Rear Drive Axle and DifferentialLesson 2 – Chassis
89Technical Training (G421061) 
						

							OPEN REAR DIFFERENTIAL ASSEMBLY
Open Rear Differential - Exploded View
(G421061) Technical Training90
Lesson 2 – ChassisRear Drive Axle and Differential 
						

							Cap1
Seal2
Bearing assembly, without race3
Bearing pre-load spacer4
Bearing5
Roller bearing cup6
Cover7
Seal8
Differential carrier9
Gear and pinion assembly10
Bearing11
Roller bearing cup12
Shim13
Collapsible spacer14
Pinion nut15
Retainer16
Flange17
Outer deflector18
Inner deflector19
Oil seal20
Bearing21
Roller bearing cup22
Roll pin23
Breather cap24
Breather25
Case26
Data location27
Mounting bush28
Bearing29
Bearing pre-load spacer30
Roller bearing cup31
Plug32
Drain plug33
Thrust washer34
Planet gears35
Crosspin shaft36
Sunwheel37
Thrust washer38
Bolt, 10 of39
Bolt, 12 of40
The cast iron casing comprises two parts; a cover and
a carrier. The carrier provides locations for all the
internal components. The carrier is sealed to the cover
via an O-ring seal and secured with twelve bolts. The
cover and carrier have cast fins, which assist mobility.
A breather tube is fitted to the top of the carrier. This
allows a plastic tube to be fitted and routed to a high
point under the vehicle body, preventing the ingress of
water when the vehicle is wading.
The carrier contains an oil drain plug. The differential
unit contains approximately 1.16 litres of oil from a dry
fill. If oil is being replaced, a smaller quantity of oil will
be required due to residual oil retained in the pinion
housing.
The differential is a conventional design using a hypoid
gear layout, similar to the front differential. The open
rear differential is available in three ratios. V8 petrol
engine vehicles use a differential with a final drive ratio
of 3.73:1, V6 petrol engine vehicles use a differential
with a final drive ratio of 3.73:1 and TdV6 engine
vehicles use a final drive ratio of 3.54, for vehicles with
automatic transmission and 3.07 for vehicles with
manual transmission. Changing the number of teeth
between the crown wheel drive gear and pinion gear
changes the ratio.
Rear Drive Axle and DifferentialLesson 2 – Chassis
91Technical Training (G421061) 
						

							The differential comprises a pinion shaft and hypoid
pinion gear and a crown wheel drive gear with an
integral cage, which houses two planet gears. Two sun
wheels are also located in the cage and pass the
rotational drive to the drive shafts.
The pinion shaft is mounted on two opposed taper roller
bearings, with a collapsable spacer located between
them. The spacer is used to hold the bearings in
alignment and also collapses under the pressure applied
to the pinion flanged nut. This allows the flanged nut
to be tightened to a predetermined torque, which
collapses the spacer, setting the correct bearing preload.
The pinion shaft has an externally splined outer end,
which accepts and locates the input flange, which is
retained by the pinion nut and retainer. The input flange
has four threaded holes and mates with the rear drive
shaft. Four bolts secure the rear drive shaft to the input
flange. An oil seal is pressed into the pinion housing
and seals the input flange to the pinion housing. The
pinion shaft has a hypoid gear at its inner end, which
mates with the crown wheel drive gear.
The crown wheel drive gear is located on the differential
case and secured with ten screws. The differential case
is mounted on taper roller bearings located in machined
bores on each side of the pinion housing. Shims are
retained in the casing behind the bearing cups, the shim
thickness is selected to apply the correct bearing preload
and hypoid backlash.
The differential carrier has a through hole, which
provides location for the shaft. The shaft is supported
by a sun gear and a needle roller bearing. The shaft is
fitted with a snap ring at one end, which locates in a
machined groove in the sun gear, locking the shaft in
position.
The sun gears are located in pockets in the carrier cage
and mesh with the planet gears. Spacers are fitted
between the sun wheels and the carrier and set the
correct mesh contact between the planet gears and the
sun wheels. Each sun wheel has a machined bore with
internal splines and machined groove near the splined
end. The groove provides positive location for a snap
ring fitted to the end of each output flange.
Each output shaft has a spline, which locates in each
sun wheel. A snap ring fitted to the splined shaft locates
in the groove the sun wheel bore and positively located
the output shaft. Oil seals are pressed into each side of
the pinion housing and seal the seal the output shaft.
Differential Operation
The operating principles of the front and rear
differentials are the same. Rotational input from the
drive shaft is passed via the input flange to the pinion
shaft and pinion gear. The angles of the pinion gear to
the crown wheel drive gear moves the rotational
direction through 90°.
The transferred rotational motion is now passed to the
crown wheel drive gear, which in turn rotates the
differential casing. The shaft, which is secured to the
casing, also rotates at the same speed as the casing. The
planet gears, which are mounted on the shaft, also rotate
with the casing. In turn, the planet gears transfer their
rotational motion to the left and right hand sun wheels,
rotating the drive halfshafts.
When the vehicle is moving in a forward direction, the
torque applied through the differential to each sun wheel
is equal. In this condition both drive halfshafts rotate at
the same speed. The planet gears do not rotate and
effectively lock the sun wheels to the differential casing.
If the vehicle is turning, the outer wheel will be forced
to rotate faster than the inner wheel by having a greater
distance to travel. The differential senses the torque
difference between the sun wheels. The planet gears
rotate on their axes to allow the outer wheel to rotate
faster than the inner one.
(G421061) Technical Training92
Lesson 2 – ChassisRear Drive Axle and Differential 
						

							SERVICE
The oil used in the open rear differential is Castrol
SAF-XO. The oil contains unique additives, which
enhance the differentials operation. No other oil must
be used in the open rear differential.
Open Rear Differential Serviceable Components
•Needle roller bearing assemblies
•Halfshaft seals
•Chassis bush/fixings
•Lubricant.
Rear Drive Axle and DifferentialLesson 2 – Chassis
93Technical Training (G421061) 
						

							ELECTRONIC REAR DIFFERENTIAL ASSEMBLY
Electronic Rear Differential - Exploded View
(G421061) Technical Training94
Lesson 2 – ChassisRear Drive Axle and Differential 
						

							Cap1
O ring2
Bearing pre-load spacer3
Bearing4
Bearing cup5
Bolt, 4 of6
Housing and motor assembly7
Damper8
Gear and pinion assembly9
Bearing10
Bearing cup11
Shim12
Collapsible spacer13
Pinion nut14
Retainer15
Flange16
Deflector, outer17
Deflector, inner18
Seal19
Bearing20
Bearing cup21
Breather cap22
Breather23
Case24
Data location25
Mounting bush26
Bearing27
Bearing assembly without race28
Bearing cup29
Filler plug30
Drain plug31
Electronic differential assembly32
Bolt, 10 of33
O ring34
Cover35
Bolt, 12 of36
Temperature sensor37
The electronic rear differential has the same
functionality as the open rear differential but
incorporates a locking feature.
An electronically controlled multi-plate clutch provides
a rear differential lock and torque biasing function to
give improved traction performance and vehicle
dynamic stability.
A strategy, to electronically control the rear differential
multi-plate clutch assembly, has been developed to
provide:
•a pre-loading function, increasing locking torque
with increased driving torque
•a slip controller to increase locking torque under
off-road conditions and decrease locking torque for
optimum comfort, e.g. parking.
The unit receives a torque input from the transfer box
output shaft, which is passed through the unit to two
outputs for the rear drive halfshafts.
The unit detects wheel slip via various vehicle system
inputs to the electronic rear differential control module
and locks the differential accordingly.
Rear Drive Axle and DifferentialLesson 2 – Chassis
95Technical Training (G421061) 
						

							Actuator1
Clutch pack2
Differential3
The electronic rear differential locking and biasing
feature is actuated via a DC motor, which is controlled
by the electronic rear differential control module, via a
Pulse Width Modulation (PWM) signal.
(G421061) Technical Training96
Lesson 2 – ChassisRear Drive Axle and Differential