2002 LAND ROVER DISCOVERY Workshop Manual

TRANSFER BOX - LT230SE
41-60 OVERHAUL
Input gear/bearing
$% 41.20.60
Disassembly
1.Make alignment marks between cover plate/
bearing housing and main casing.
2.Remove 5 bolts and stud nut securing cover/
bearing housing to main casing. Remove cover
and bearing housing.
3.Remove input gear assembly. 4.Remove and discard oil seal from main casing.
5.Drift out bearing track from main casing.

TRANSFER BOX - LT230SE
OVERHAUL 41-61
6.Drift out bearing track from housing and collect
selective shim.
7.Position tool LRT-99-002 to vice.
8.Assemble tool LRT-41-003 to bearing, position
input gear to hand press and remove bearing.
9.Repeat procedure for remaining bearing.
Reassembly
1.Clean input gear, cover/bearing housing and
main casing. 2.Using tool LRT-99-002 and LRT-41-003 fit
new bearings to input gear.
3.Using a suitable mandrel, fit bearing track to
main casing.
4.Fit a 3.15 mm (0.12 in) thick shim to bearing
housing and using a suitable mandrel fit
bearing track to housing.
5.Position input gear to main casing.
6.Fit bearing housing, ensuring reference marks
are aligned, secure bearing housing with 2
bolts and tighten to 25 Nm (18 lbf.ft).

TRANSFER BOX - LT230SE
41-62 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 3254 to bearing
housing and cover.
15.Position bearing housing/cover, align reference
marks and tighten by diagonal selection to 45
Nm (33 lbf.ft).
16.Using tool LRT-37-014 fit new input shaft oil
seal.
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.

TRANSFER BOX - LT230SE
OVERHAUL 41-63
7.Remove high range gear and bush.
8.Make suitable alignment marks between high/
low selector sleeve and hub, remove selector
sleeve. 9.Using a suitable press and thrust button LRT-
41-001remove high/low hub and low range
gear.
Reassembly
1.Clean differential components.
2.Lubricate components with gearbox oil.
3.Fit differential in soft jawed vice, and fit low
range gear with dog teeth facing uppermost.
4.Fit high/low hub ensuring that machined
groove on hub teeth faces towards low range
gear.
5.Fit high/low selector sleeve ensuring that
alignment marks on hub and sleeve are
together.
6.Fit bush to high range gear ensuring collar is
uppermost.
7.Fit high range gear and bush onto shaft.

TRANSFER BOX - LT230SE
41-64 OVERHAUL
8.Fit rear bearing using tool LRT-41-008.
9.Fit new bearing retaining nut and using tool
LRT-41-007, tighten to 72 Nm (53 lbf.ft).
10.Using a suitable drift, stake collar of nut into
differential shaft recess.
11.Fit high/low selector shaft detent ball and
spring.
12.Apply Loctite 290 sealant to threads of detent
plug.
13.Fit and tighten plug, then loosen 2 complete
turns.
14.Fit differential.

+ TRANSFER BOX - LT230SE,
OVERHAUL, Differential assembly.

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 switch
5Oil 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