1999 LAND ROVER DISCOVERY lock

TRANSFER BOX - LT230SE
OVERHAUL 41-65
9. 03 Model Year onwards:Note position of
longest bolt and remove 8 bolts securing front
output shaft housing to main casing; remove
housing.
10. 03 Model Year onwards:Remove 3 bolts
securing differential lock selector housing and
bracket, remove housing.
11. 03 Model Year onwards:Remove and discard
'O' rings from selector housing.
12. 03 Model Year onwards:Remove differential
lock detent plug, recover spring and ball.
13.Compress differential lock selector fork spring
and remove retaining clips from each end of
spring.
14.Withdraw differential lock selector shaft from
front output housing, recover spring and
remove selector fork.
15.Position tool LRT-51-003 to output shaft drive
flange, remove and discard nut. 16.Remove and discard steel and felt washers.
Remove output shaft drive flange.
17.Using a copper mallet, drive output shaft from
housing.
18.Noting its fitted position, remove bearing
spacer from output shaft.
19.Noting its fitted position, remove dog clutch
from output shaft.
20.Remove and discard oil seal from housing.
Reassembly
1.Clean differential lock components. Remove all
traces of sealant from mating faces of
housings, side cover, bolt threads, detent plugs
and differential lock warning lamp switches.
2.Lubricate components with gearbox oil.
3.Using tool LRT-41-012, fit new output shaft oil
seal.
CAUTION: Oil seal must be fitted dry.

TRANSFER BOX - LT230SE
41-66 OVERHAUL
4.Fit bearing spacer to output shaft with chamfer
on spacer towards threaded end.
5.Fit dog clutch with flange on clutch facing
towards splined end.
6.Using a copper mallet, drive output shaft into
bearing.
7.Compress differential lock selector spring and
fit selector fork.
8.Position selector fork to groove in dog clutch.
9.Fit differential lock selector shaft and locate in
housing recess, rotate shaft until the two flats
for retaining clips are at right angles to the
cover plate mating face.
10.Compress differential lock selector spring and
fit retaining clips at each end of spring.
CAUTION: Ensure ends of spring are fully
seated in recess in clips.
11.Apply sealant, Part No. STC 4600 to front
output shaft housing.
12.Position housing ensuring that output shaft and
dog clutch splines are correctly engaged.
13.Apply sealant, Part No. STC 50552 to threads
of bolts.
14.Fit front output shaft housing bolts and tighten
in a diagonal sequence to 45 Nm (33 lbf.ft).
15.Apply sealant, Part No. STC 4600 to mating
face of high/low selector housing.
16.Position high/low selector housing to front
output housing ensuring that high/low selector
finger is located in groove in selector shaft.
17. Position multiplug and selector cable brackets
to high/low selector housing
18.Apply sealant, Part No. STC 50552 to threads
of high/low selector housing bolts.
19.Fit bolts and tighten to 25 Nm (18 lbf.ft).20.Fit differential lock detent ball and spring.
21. Up to 03 Model Year: Apply sealant, Part No.
STC 50552 to threads of detent plug.
22. Up to 03 Model Year: Fit and tighten detent
plug, then unscrew 2 complete turns.
23. 03 Model Year onwards: Apply sealant, Part
No. STC 50552 to threads of differential lock
detent plug.
24.Fit differential lock detent ball and spring.
25.Fit detent plug and tighten until head of plug is
level with face of housing.
26.Using a suitable straight edge, check that head
of plug is correctly positioned, screw plug in or
out as necessary.
27.Lubricate and fit new 'O' rings to differential lock
selector housing.
28.Fit selector housing, ensure selector finger is
located in shaft recess.
29.Position bracket to selector housing.
30.Apply sealant, Part No. STC 50552 to threads
of selector housing bolts, fit bolts and tighten to
25 Nm (18 lbf.ft).
M41 7886

TRANSFER BOX - LT230SE
OVERHAUL 41-67
31.Clean threads of differential lock warning lamp
switch(es).
32. Uo to 03 Model year: Fit nut to switch head
with counterbore positioned towards switch
head. The nut acts as a spacer to ensure
that switch setting is correct. Always
ensure that nut is fully tightened to switch
head (no gap).
33. Uo to 03 Model year: Apply sealant, Part No.
STC 50552 to threads of differential warning
lamp switch.
34. Uo to 03 Model year: Position switch into front
output housing until nut bottoms out on
housing, tighten nut to 11 Nm (8 lbf.ft).
35. 03 Model Year onwards: Fit new aluminium
sealing washers to differential lock warning
lamp switches.
CAUTION: Ensure that replacement
washers are the same thickness as the
originals.
36. 03 Model Year onwards: Apply sealant, Part
No. STC 50552 to threads of both switches.
37. 03 Model Year onwards: Fit switches and
tighten to 25 Nm (18 lbf.ft).
38. If fitted: Operate differential lock selector lever
and check that detent ball can be felt to
positively engage/disengage with grooves in
shaft.
39. Up to 03 Model Year: Screw plug in or out until
setting is correct
40.Apply sealant, Part No. STC 4600 to mating
face of differential lock selector side cover.
41.Apply sealant, Part No. STC 50552 to threads
of side cover bolts.
42.Position differential lock selector side cover to
front output shaft housing, fit bolts and tighten
25 Nm (18 lbf.ft).43.Fit output flange, new felt and steel washers
and new retaining nut.
44.Using tool LRT-51-003 to restrain flange,
tighten output flange nut to 162 Nm (119 lbf.ft).

TRANSFER BOX - LT230SE
41-70 OVERHAUL
7.Position dial gauge with stylus contacting input
gear, push input gear rearwards and zero
gauge.
8.Push input gear forwards and note gauge
reading.
9.Calculate thickness of shim required using the
formula - A+B+C=D where:
lA= Thickness of installed shim - 3.15 mm
(0.12 in)
lB= Recorded end-float.
lC= Required pre-load - 0.05 mm (0.002 in).
lD= Thickness of shim required.
10.If an alternative shim is required to establish
correct pre-load, fit an alternative shim. Shims
are available from 3.15 to 4.00 mm (0.12 to
0.16 in) thickness, in increments of 0.05 mm
(0.002 in).
11.Remove 2 bolts, remove bearing housing and
input gear.
12.Lubricate input gear and bearings with
recommended oil.
13.Position input gear into main casing.
14.Apply sealant, Part No. STC 4600to bearing
housing and cover.
15.Apply sealant, Part No. STC 50552 to threads
of cover bolts and stud nut.
16.Position bearing housing/cover, align reference
marks and tighten bolts and stud nut by
diagonal selection to 45 Nm (33 lbf.ft).
17.Using tool LRT-37-014 fit new input shaft oil
seal.
CAUTION: Oil seal must be fitted dry.
Low gear - differential
$% 41.20.62
Disassembly
1.Remove differential.

+ TRANSFER BOX - LT230SE,
OVERHAUL, Dog clutch - differential lock.
2.Secure differential in a soft jawed vice.
3.Release staking from bearing retaining nut.
4.Using tool LRT-41-007 remove and discard
bearing retaining nut.
5.Position tool LRT-99-002. to a vice.
6.Position tool LRT-41-001 around rear
differential bearing, position differential to tool
LRT-99-002 and press off bearing.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-4 DESCRIPTION AND OPERATION
Description
General
The automatic gearbox is a four speed unit with electronic control of gear selection, shift quality and torque converter
lock-up. Selections on the selector lever assembly are transmitted to the gearbox by a selector cable. A gear position
switch on the gearbox transmits the gear selection to an Electronic Automatic Transmission (EAT) ECU, which
outputs the appropriate control signals to an electro-hydraulic valve block in the gearbox. A mode switch enables the
driver to change the control mode of the EAT ECU. The EAT ECU operates warning lamps in the instrument pack to
indicate the control mode and system status.
The gearbox features a pressure lubrication system and is cooled by pumping the lubricant through an oil cooler.
On NAS market vehicles from 03 model year, the ZF 4HP24 transmission unit is introduced for use with the 4.6 litre
V8 engine. This transmission is required to accomodate the increased power output of the larger engine. The ZF
4HP22 transmission remains in use on vehicles with Td5 and 4.0 litre V8 engines.
Both transmission units are of similar construction, with the ZF 4HP24 unit being 15 mm longer than the 4HP22 unit
to accomodate a larger fluid pump. The operation of both transmission units is the same.

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-5
Selector lever assembly
1Release button
2Mode switch
3Electrical connector
4Interlock solenoid (where fitted)
5Base6Gasket
7Securing bolt
8Lever
9Cover
10Position indicators
The selector lever assembly consists of a lever and a cover attached to a base. The base is located on a gasket and
secured to the transmission tunnel. The lever is hinged to the base. A latch in the lever engages with detents in the
base to provide the lever positions P, R, N, D, 3, 2, 1. The latch is disengaged by pressing a release button on the
lever knob. Except for lever movement between positions D and 3, the button must be pressed before the lever can
be moved. In some markets, vehicles incorporate an interlock solenoid at the bottom of the lever, which prevents the
lever being moved from P unless the ignition switch is in position II and the foot brake is applied. If the battery
becomes flat, the interlock system will prevent selector lever movement and removal of the ignition key.
The cover incorporates lever position indicators and the mode switch. The lever position indicators illuminate to show
the position of the selector lever. Illumination is controlled by the Body Control Unit (BCU). The mode switch is a non-
latching hinged switch that, when pressed, connects an earth to the EAT ECU to request a change of mode.
An electrical connector at the rear of the cover connects the selector lever assembly to the vehicle wiring.
Selector cable
The selector cable is a Bowden type cable that connects the selector lever assembly to a selector lever on the
gearbox. 'C' clips secure the ends of the outer cable to brackets on the selector lever assembly and the selector lever.
The inner cable is adjustable at the connection of the inner cable with the gearbox selector lever.

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-7
The gearbox consists of a torque converter housing, an intermediate plate, a gearbox housing and a rear extension
housing, bolted together in series. The rear of the gearbox is supported by a rubber mounting installed between a
mounting bracket on the gearbox and the LH chassis rail. A heat shield is installed on the mounting to protect it from
the exhaust.
Sectioned view of gearbox
1Lock-up clutch
2Impeller
3Turbine
4Forward drive clutch
5Reverse drive clutch
6Brake clutch
7Brake clutch
8Brake clutch
9Epicyclic gear set10Epicyclic gear set
11Clutch
12Brake clutch
13Output shaft
14Freewheel (one way clutch)
15Freewheel (one way clutch)
16Freewheel (one way clutch)
17Stator and one way clutch
Torque converter housing
The torque converter housing attaches the gearbox to the engine and contains the torque converter. Different torque
converter housings are used to accommodate the difference between the V8 and Td5 engine interfaces. The torque
converter is connected to the engine drive plate and transmits the drive from the engine to the gearbox input shaft.
When engaged, a hydraulic lock-up clutch in the torque converter prevents slippage, to give a direct drive from the
engine to the gearbox for improved driving response.
Intermediate plate
The intermediate plate supports the gearbox input shaft and provides the interface between the transmission fluid
pump and the lubrication circuit. The pump attaches to the front of the intermediate plate and is driven by the impeller
in the torque converter. The pump pressurises transmission fluid drawn from the sump on the gearbox housing. The
pressurised fluid then circulates through the torque converter and gearbox housing components for cooling,
lubrication and gear shift purposes. Ports around the outer periphery of the intermediate plate provide the inlet and
outlet connections to the fluid cooler and a pressure take-off point for servicing.

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