1999 LAND ROVER DISCOVERY oil

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 44-13
Oil cooler
1Inlet connection
2Fixing bracket
3Outlet connection4Fixing 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
44-26 REPAIRS
Seal - selector shaft
$% 44.15.34
Remove
1.Remove valve body assembly.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.
2.Remove nut securing selector shaft lever and
release lever from shaft.
3.Remove 2 bolts securing gear selector switch
to gearbox and remove switch.
4.Drift out and discard selector quadrant roll pin.
Remove selector shaft.
5.Remove selector quadrant and connecting rod.
6.Remove oil seal taking care not to damage
seal housing. Refit
1.Clean shaft and seal housing.
2.Using a suitable adapter, fit new seal.
3.Position selector quadrant and connecting rod.
4.Position selector shaft and secure to quadrant
using new roll pin.
5.Fit valve body assembly.
+ AUTOMATIC GEARBOX - ZF4HP22
- 24, REPAIRS, Valve body assembly.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-27
Gearbox - convertor and transfer
gearbox - Diesel
$% 44.20.04.99
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Raise vehicle on a ramp.
4.Remove starter motor.

+ CHARGING AND STARTING,
REPAIRS, Starter motor - diesel.
5.Remove 2 upper bolts securing gearbox
housing to engine.
6.Remove bolt securing closing plate to gearbox
housing.
7.Remove exhaust front pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - Td5, REPAIRS, Pipe - front.
8.Remove 3 nuts securing intermediate silencer
to tail pipe.
9.Release and remove silencer from rubber
mountings. 10.Drain automatic gearbox oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
11.Drain transfer gearbox oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
12.Remove front propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.
13.Remove rear propeller shaft.

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
14.Remove and discard 3 bolts securing torque
converter to drive plate.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-29
24. 03 Model Year onwards - If fitted: Release
and disconnect both differential lock warning
lamp switch multiplugs from main harness.
25.Remove cable tie and multiplug from bracket
on transfer box.
26.Release transfer and automatic gearbox
breather pipes from clip at rear of cylinder
block.
27.Position gearbox support jack and secure tool
LRT-99-008A to support plate on jack. 28.Position a second support jack under engine
using a block between engine sump and jack
to prevent damage to sump.
29.Remove 4 bolts and nut, remove engine LH
rear mounting.
30.Remove 4 bolts and nut, remove engine RH
rear mounting.
31.Remove 2 bolts securing gearbox oil cooler
pipe clips to engine sump and alternator
mounting bracket.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-30 REPAIRS
32.Remove bolt and 2 nuts securing clamps to oil
cooler pipes and remove clamps.
33.Loosen gearbox oil cooler pipe unions, release
pipes from gearbox and discard 'O' rings.
CAUTION: Always fit plugs to open
connections to prevent contamination.34.Remove 'C' clip securing selector cable to
gearbox bracket.
35.Remove nut securing selector lever to inhibitor
switch and release lever.
36.Disconnect multiplug from inhibitor switch.
37.Loosen gearbox multi plug locking ring and
disconnect plug.
38.Remove 6 remaining gearbox housing bolts.
39.With assistance remove automatic gearbox
from engine.

AUTOMATIC GEARBOX - ZF4HP22 - 24
REPAIRS 44-31
40.Fit suitable strap to retain torque converter.
Refit
1.Clean gearbox to engine mating faces.
2.Remove torque converter retaining strap.
3.With assistance position gearbox to engine.
4.Fit but do not tighten six bolts securing gearbox
housing to engine.
5.Connect multiplug to gearbox and tighten
locking ring.
6.Connect multiplug to inhibitor switch.
7. If fitted: Connect and adjust differential lock
selector cable.

+ TRANSFER BOX - LT230SE,
ADJUSTMENTS, Cable - selector -
differential lock - adjust.
8.Position selector lever to inhibitor switch and
tighten nut to 25 Nm (18 lbf.ft).
9.Position selector cable to gearbox and secure
with 'C' clip.
10.Clean oil pipe unions and fit new 'O' rings.
11.Position and tighten pipe unions to gearbox.
12.Position and tighten oil cooler pipe clamps.
13.Position and tighten oil cooler pipe clips to
engine sump and alternator bracket.
14.Position engine RH and LH rear mountings
and tighten bolts to 85 Nm (63 lbf.ft) and nuts to
85 Nm (63 lbf.ft).
15.Secure gearbox breather pipes to bulkhead
clip.
16. Up to 03 Model Year - If fitted: Connect 2
Lucars to differential lock warning lamp switch
and multiplugs to high/low ratio switch and
neutral sensor.
17. 03 Model Year onwards - If fitted: Connect
differential lock warning lamp switch multiplugs
to main harness.
18.Position cable tie and multiplug to transfer box
bracket.
19.Connect high/low ratio selector cable to
selector lever and secure with clevis pin. 20.Position high/low ratio selector cable to
abutment bracket and secure with 'C' clip.
21. Models fitted with high/low shift interlock
solenoid: Position interlock solenoid harness
to high/low shift cable, fit sleeve around cable
and harness.
22. Models fitted with high/low shift interlock
solenoid: Connect solenoid multiplug to main
harness and secure multiplug to bracket.
23.Position handbrake backplate and tighten bolts
to 75 Nm (55 lbf.ft).
24.Fit hand brake drum and tighten screw.
25.Remove bolts securing tool LRT-99-008A to
gearbox.
26.Rotate engine to align torque converter, fit new
bolts and tighten to 50 Nm (37 lbf.ft).
27.Fit rear propeller shaft.

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

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.
29.Fill transfer gearbox with oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
30.Fill automatic gearbox with oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
31.Position intermediate silencer and secure to
mounting rubbers.
32.Clean silencer and tail pipe mating faces.
33.Position new gasket to tail pipe and tighten
nuts to 25 Nm (18 lbf.ft).
34.Fit exhaust front pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - Td5, REPAIRS, Pipe - front.
35.Fit bolt securing closing plate to gearbox
housing and tighten to 7 Nm (5.2 lbf.ft).
36.Fit upper bolts securing gearbox housing to
engine and tighten to 50 Nm (37 lbf.ft).
37.Fit starter motor.

+ CHARGING AND STARTING,
REPAIRS, Starter motor - diesel.
38.Tighten remaining gearbox housing to engine
bolts to 50 Nm (37 lbf.ft).
39.Connect battery earth lead.
40.Fit battery cover and secure with fixings.
41.Check and adjust selector cable.

+ AUTOMATIC GEARBOX - ZF4HP22
- 24, ADJUSTMENTS, Cable - selector.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-32 REPAIRS
Gearbox - convertor and transfer
gearbox - V8
$% 44.20.04.99
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3.Raise vehicle on a ramp.
4.Remove 8 bolts securing centre cross member
and remove cross member.
5.Remove exhaust front pipe.

+ MANIFOLDS AND EXHAUST
SYSTEMS - V8, REPAIRS, Front pipe.
6.Remove 3 nuts securing intermediate silencer
to tail pipe.
7.Release and remove silencer from rubber
mountings.
8.Drain automatic gearbox oil.

+ MAINTENANCE, PROCEDURES,
Automatic gearbox.
9.Drain transfer gearbox oil.

+ MAINTENANCE, PROCEDURES,
Transfer box.
10.Remove front propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - front.11.Remove rear propeller shaft

+ PROPELLER SHAFTS, REPAIRS,
Propeller shaft - rear.
12.Remove plug from torque converter housing to
access torque converter bolts.
13.Remove and discard 4 bolts securing torque
converter to drive plate.
14.Remove hand brake drum retaining screw and
remove brake drum.
15.Remove 4 bolts from hand brake back plate,
release back plate and tie aside.