1999 LAND ROVER DISCOVERY Gear ratio

TRANSFER BOX - LT230SE
41-30 REPAIRS
12. If fitted: Release and remove clevis pin
securing differential lock selector cable to
transfer gearbox.
13. If fitted: Loosen locknuts securing differential
lock selector cable to differential lock selector
cable abutment bracket.
14. If fitted: Release and remove differential lock
selector cable from differential lock selector
cable abutment bracket.
15.Remove clevis pin and 'C' clip securing high/
low ratio selector cable to selector lever and
release cable from abutment bracket.
16.Remove 2 cable ties securing cable to fuel
pipes. 17. If fitted: Disconnect 2 Lucars from oil
temperature sensor and disconnect reverse
lamp switch multiplug.
18.Remove banjo bolt securing breather pipe and
discard washers.
19. Up to 03 Model Year - if fitted: Disconnect 2
Lucars from differential lock switch and
multiplugs from high/low ratio switch and
neutral sensor.
20.Disconnect multiplug from reverse light switch.

TRANSFER BOX - LT230SE
REPAIRS 41-31
21. 03 Model Year onwards - if fitted: Release
and disconnect both differential lock warning
lamp switch multiplugs from main harness.
22.Remove 4 bolts from transfer box bottom plate,
position support plate LRT-99-010 to transfer
box and tighten bolts.
23.Position gearbox support jack and secure
support plate to jack using 4 bolts. 24.Remove 3 bolts securing transfer box to
gearbox.
25.Fit 3 guide studs LRT-41-009 through transfer
box bolt holes to support it during removal.
26.Remove 2 bolts and nut securing transfer box
to gearbox case.
CAUTION: If securing stud is removed
during this operation, it must be discarded
and a new stud fitted.
27.Position a jack to support gearbox and engine.
28.Remove 4 bolts and nut securing RH mounting
to body and transfer box.
29.Remove nut securing LH mounting to body.
30.Raise gearbox and remove RH mounting.
31.With assistance, remove transfer box from
gearbox.
32.Remove input shaft oil seal.

+ TRANSFER BOX - LT230SE,
REPAIRS, Oil seal - input shaft.

TRANSFER BOX - LT230SE
41-32 REPAIRS
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 sealant, Part No. STC 50552 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 sealant, Part No. STC 50552 to
stud threads 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 sealant, Part No. STC 50552 to threads
of 4 bottom plate 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. Up to 03 Model Year - if fitted : Connect
Lucars to differential lock switch and multiplugs
to high/low ratio switch and neutral sensor.
20. 03 Model Year onwards - if fitted: Connect
differential lock warning lamp multiplugs,
secure harness.
21.Connect multiplug to reverse lamp switch.
22. If fitted: Connect Lucars to oil temperature
switch.
23.Position high/low ratio selector cable and
secure with 'C' clip and clevis pin.
24. If fitted: Position differential lock selector cable
to differential lock selector cable abutment
bracket and tighten locknuts sufficiently to
retain cable.
25. If fitted: Fit differential lock selector cable to
transfer gearbox and secure with clevis pin.
26. If fitted: Adjust differential lock selector cable.

+ TRANSFER BOX - LT230SE,
ADJUSTMENTS, Cable - selector -
differential lock - adjust.27. Models fitted with high/low shift interlock
solenoid: Position interlock solenoid harness
to high/low shift cable, fit sleeve around cable
and harness; secure sleeve.
28. Models fitted with high/low shift interlock
solenoid: Connect solenoid multiplug to main
harness and secure multiplug to bracket.
29.Secure cable to fuel pipes with new cable ties.
30.Clean handbrake back plate and mating face.
31.Position handbrake back plate, fit bolts and
tighten to 75 Nm (55 lbf.ft).
32.Clean handbrake drum.
33.Fit handbrake drum and tighten retaining
screw.
34.Fit front propeller shaft.

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

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

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

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

AUTOMATIC GEARBOX - ZF4HP22 - 24
DESCRIPTION AND OPERATION 44-1
AUTOMATIC GE ARBOX - ZF4HP22 - 24 DESCRIPTION AND OPERAT ION
Automatic gearbox component layout
1Selector lever assembly
2Gearbox
3Electronic automatic transmission ECU
4Selector position switch5Oil cooler
6Fluid lines
7Breather tube
8Selector cable

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-2 DESCRIPTION AND OPERATION
Control schematic

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
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.