2002 LAND ROVER DISCOVERY sensor

TRANSFER BOX - LT230SE
REPAIRS 41-29
22.Remove 4 bolts and nut securing RH mounting
to body and transfer box.
23.Remove nut securing LH mounting to body.
24.Raise gearbox and remove RH mounting.
25.With assistance, remove transfer box from
gearbox.
26.Remove input shaft oil seal.

+ TRANSFER BOX - LT230SE,
REPAIRS, Oil seal - input shaft.
Refit
1.Fit new input shaft oil seal.

+ TRANSFER BOX - LT230SE,
REPAIRS, Oil seal - input shaft.
2.Clean transfer box to gearbox mating faces.
3.Raise transfer box on jack and align to guide
studs LRT-41-009.
4.Clean transfer box to gearbox bolt threads.
5.Apply Loctite 290 to bolt and stud threads.
6.Fit and lightly tighten 2 bolts and nut securing
transfer box to gearbox. If new stud is to be
fitted apply Loctite 290 to threads of stud
and tighten to 45 Nm (33 lbf.ft)
7.Remove guide studs, fit and lightly tighten 3
bolts.
8.Tighten bolts and nut by diagonal selection to
45 Nm (33 lbf.ft.
9.Position gearbox RH mounting and tighten
bolts to 85 Nm (63 lbf.ft).
10.Tighten gearbox RH mounting nut to 48 Nm
(35 lbf.ft).
11.Fit nut to LH mounting and tighten to 48 Nm (35
lbf.ft).
12.Remove 4 bolts securing support plate to
gearbox jack.
13.Remove 4 bolts securing support plate LRT-99-
010 to transfer box and remove plate.
14.Clean threads of bottom plate bolts.
15.Apply Loctite 290 to threads of bolts.
16.Fit 4 bolts securing bottom plate and tighten to
25 Nm (18 lbf.ft).
17.Using new washers position breather pipe and
tighten banjo bolt.
18.Connect multiplug to transfer box neutral switch
and secure harness. 19. If fitted - Connect Lucars to differential lock
switch.
20.Connect multiplug and Lucars to reverse lamp
switch and oil temperature sensor.
21.Position high/low ratio selector cable and
secure with 'C' washer and clevis pin.
22.Secure cable to fuel pipes with new cable ties.
23.Clean handbrake back plate and mating face.
24.Position handbrake back plate, fit bolts and
tighten to 75 Nm (55 lbf.ft).
25.Clean handbrake drum.
26.Fit handbrake drum and tighten retaining
screw.
27.Fit front propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.
28.Fit rear propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
29.Clean exhaust silencer and tail pipe mating
faces.
30.Position silencer and secure on mountings,
using a new gasket align to tail pipe, fit nuts
and tighten to 25 Nm (18 lbf.ft).
31.Position rear cross member, fit bolts and
tighten to 26 Nm (19 lbf.ft).
32.Refill transfer box with oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
33.Fit front exhaust pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Front pipe.

TRANSFER BOX - LT230SE
41-36 REPAIRS
Solenoid - interlock - Up to 03 MY
$% 41.20.63
Remove
1.Raise vehicle on ramp.
2.Disconnect multiplug from interlock solenoid.
3.Release multiplug retainer from mounting plate
on transfer box.
4.Remove 4 bolts securing solenoid cover,
remove cover and Belleville washer.
5.Remove solenoid.
Refit
1.Clean solenoid cover and mating face.
2.Position solenoid in main casing.
3.Apply sealant, Part No. STC 3254 to solenoid
cover.
4.Fit cover and Belleville washer.
5.Fit bolts securing interlock solenoid and tighten
to 10 Nm (7 lbf.ft).
6.Connect and secure multiplug.
7.Lower vehicle on ramp.
Sensor - neutral
$% 41.20.64
Remove
1.Raise vehicle on ramp.
2.Disconnect multiplug from neutral sensor.
3.Remove sensor and discard sealing washer.
Refit
1.Clean sensor threads.
2.Fit new washer and apply Hylosil PL 32 to
sensor threads.
3.Fit and tighten sensor to 25 Nm (18 lbf.ft).
4.Lower vehicle on ramp.

TRANSFER BOX - LT230SE
REPAIRS 41-37
Sensor - oil temperature
$% 41.20.80
Remove
1.Lower vehicle.
2.Disconnect 2 Lucar connectors from oil
temperature sensor.
3.Remove oil temperature sensor and discard
sealing washer.
Refit
1.Clean sensor and mating face on transfer box.
2.Fit new sealing washer, position oil
temperature sensor and tighten to 42 Nm (31
lbf.ft).
3.Connect Lucar connectors to oil temperature
sensor.
4.Lower vehicle.
Switch - high low - warning
$% 41.30.05
Remove
1.Raise vehicle on a ramp.
2.Release switch multiplug from bracket on
transfer box and disconnect from harness.
3.Remove switch from transfer box and discard
sealing washer.
Refit
1.Ensure sealing washer, switch thread and
mating face on transfer box is clean.
2.Fit sealing washer to switch, fit and tighten
switch to transfer box to 26 Nm (19 lbf.ft) .
3.Connect multiplug to harness and fit multiplug
to bracket on transfer box.
4.Lower vehicle.

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-3
1Transmission high/low switch
2Mode switch
3Gear position switch connector
4Solenoid valve/speed sensor connector
5Electronic automatic transmission ECU
6Engine control module
7Diagnostic socket
8Instrument pack
9Transmission fluid temperature sensor
10Body control unit
11Battery power supply
12Ignition power supply

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-9
Valve block
1Valve block
2Pressure regulating solenoid valve (MV 4)
3Shift control solenoid valve (MV 2)
4Shift control solenoid valve (MV 1)
5Lock-up solenoid valve (MV 3)
6Output shaft speed sensor
7Bolt
8Sensor retaining clip9Manual valve
10'O' ring
11Filter
12'O' ring
13Suction pipe
14Bolt
15Bolt
16Washer

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-10 DESCRIPTION AND OPERATION
The lock-up and brake clutches are operated by pressurised transmission fluid from the valve block in the sump. A
manual valve and four solenoid valves, also known as Motorised Valves (MV), control the supply of pressurised
transmission fluid from the valve block:
lThe manual valve controls the supply in P, R, N and D.
lSolenoid valves MV 1 and MV 2 control the supplies that operate the brake clutches for shift control.
lSolenoid valve MV 3 controls the supply that operates the lock-up clutch.
lSolenoid valve MV 4 modulates the pressure of the supplies to the brake clutches, to control shift quality.
Operation of the manual valve is controlled by the selector lever assembly. In the gearbox, a selector shaft engages
with the manual valve. The selector shaft is connected to the selector lever assembly via the selector cable and a
selector lever on the left side of the gearbox. The selector shaft also operates a mechanism that locks the output shaft
when P is selected.
Operation of the solenoid valves is controlled by the EAT ECU.
An output shaft speed sensor in the gearbox housing outputs a signal to the EAT ECU. The EAT ECU compares
output shaft speed with engine speed to determine the engaged gear, and output shaft speed with vehicle speed to
confirm the range selected on the transfer box.
A bayonet lock electrical connector in the gearbox casing, to the rear of the selector lever, connects the solenoid
valves and the output shaft speed sensor to the vehicle wiring.
A pressed steel sump encloses the valve block and collects transmission fluid draining from the gearbox housing. A
suction pipe and filter on the underside of the valve block connect to the inlet side of the fluid pump. A magnet is
installed in the sump to collect any magnetic particles that may be present. A level plug and a drain plug are installed
in the sump for servicing.
Rear extension housing
The rear extension housing provides the interface between the gearbox housing and the transfer box. A splined
extension shaft, secured to the gearbox output shaft by a bolt, transmits the drive from the gearbox to the transfer
box. A seal in the rear of the housing prevents leakage past the extension shaft. A breather pipe, attached to the left
side of the rear extension housing, ventilates the interior of the gearbox and rear extension housings to atmosphere.
The open end of the breather pipe is located in the engine compartment at the right front corner of the engine sump
on gearboxes fitted to early vehicles and is clipped to the top of the gearbox on later vehicles.
Gearbox power flows
The following Figures show the power flow through the gearbox for each forward gear when D is selected, and for
reverse. The key to the Item numbers on the Figures, and in parenthesis in the accompanying text, can be found on
the 'Sectioned view of gearbox' Figure, above.
1st Gear (D selected)
Clutches (4) and (11) are engaged. The front planet gear carrier of gear set (9) locks against the gearbox housing
through freewheel (15) when the engine powers the vehicle, and freewheels when the vehicle is coasting. Gear set
(10) rotates as a solid unit with the front planet gear carrier. In 1st gear hold brake clutch (8) is applied to provide
overrun braking.

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-13
Oil cooler
1Inlet connection
2Fixing bracket
3Outlet connection
4Fixing bracket
5Temperature sensor
Transmission fluid from the gearbox is circulated through a cooler attached to the front of the radiator. Quick release
connectors on the transmission fluid lines attach to connections on each end tank of the cooler. A temperature sensor
on the RH end tank provides the instrument pack with an input of transmission fluid temperature. If the temperature
exceeds a preset limit, the instrument pack illuminates the transmission temperature warning lamp. The warning lamp
remains illuminated until the temperature of the fluid returns within limits.
EAT ECU
The EAT ECU operates the solenoid valves in the gearbox to provide automatic control of gear shifts and torque
converter lock-up. The EAT ECU is attached to a protective bracket which is secured to the cabin floor below the LH
front seat. A 55 pin connector links the EAT ECU to the vehicle wiring.
Software in the EAT ECU monitors hard wired inputs and exchanges information with the ECM on a Controller Area
Network (CAN) bus to determine gear shift and torque converter lock-up requirements. Resultant control signals are
then output to the gearbox solenoid valves.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-14 DESCRIPTION AND OPERATION
EAT ECU connector
EAT ECU connector pin details
Pin No. Description Inputs/Outputs
1 to 4 Not used-
5 Pressure regulator solenoid valve (MV 4) Output
6 Power earth -
7 Not used-
8 Gear position switch, X contacts Input
9 Gear position switch, Z contacts Input
10 to 12 Not used-
13 Transmission high/low switch Input
14 Gearbox output shaft speed sensor, negative Input
15 Gearbox output shaft speed sensor cable screen -
16 CAN, high Input/Output
17 to 24 Not used-
25 Sport mode warning lamp Output
26 Battery power supply Input
27 Not used-
28 Electronics earth -
29 Not used-
30 Shift control solenoid valve (MV 1) Output
31 Diagnostics, K line Input/Output
32 Converter lock-up solenoid valve (MV 3) Output
33 Shift control solenoid valve (MV 2) Output
34 Not used-
35 Not used-
36 Gear position switch, W contacts Input
37 Gear position switch, Y contacts Input
38 to 41 Not used-
42 Gearbox output shaft speed sensor, positive Input
43 Not used-
44 CAN, low Input/Output
45 Mode switch Input
46 to 50 Not used-
51 Manual mode warning lamp Output
52 Not used-
53 Solenoid valves power supply Output
54 Ignition power supply Input
55 Not used-