1996 LAND ROVER DEFENDER gearbox

TRANSFER GEARBOX
1
DESCRIPTION AND OPERATION TRANSFER GEARBOX
Description
The transfer gearbox is a permanent 4 wheel drive,
two speed ratio reducing gearbox, incorporating high
and low range outputs with mechanically lockable
centre differential (diff-lock). High/low range and
diff-lock selection are made via a single lever located
forward of the main gear lever.
The transfer gearbox is mounted at the rear of the
main gearbox, the mainshaft of which extends into the
transfer casing. A transfer gear, supported on taper
roller bearings and splined to the gearbox mainshaft,
passes the drive to an intermediate gear cluster
supported on a single shaft and rotating on taper roller
bearings.The intermediate gears pass the drive to high and low
speed gears on the rear output shaft. The rear output
shaft passes through the speedo drive housing, which
also forms the mounting for the transmission brake. A
worm gear fitted to the rear output shaft drives a
pinion fitted in the speedo housing.
Integral with the output shafts is a differential
assembly which compensates for speed differences
between the front and rear prop shafts. To prevent all
the power being transmitted to the axle offering the
least resistance, a diff-lock is provided. The differential
lock should only be engaged during severe off-road
conditions and should be disengaged as soon as
conditions permit. Selection of differential lock
engages, through mechanical linkage, a dog clutch
with the front output shaft, this action locks the centre
differential and provides a fixed drive, giving equal
power to the front and rear output shafts.

TRANSFER GEARBOX
1
FAULT DIAGNOSIS TRANSFER GEARBOX - OIL SEAL LOCATIONS
1.Input seal.
2.Cover plate joints.
3.Front output seal.
4.Front and rear housing joint faces.5.Rear output seal.
6.Power take off cover plate joint.
7.Bearing plate joint.

41TRANSFER GEARBOX
2
FAULT DIAGNOSIS OIL LEAKS
Verify that oil leak is from transfer box and not main
gearbox before proceeding with checks.
Prior to road test
1.Check oil level in transfer box is correct.
2.Check tightness of level and drain plugs.
3.Check breather system for blockage. To validate
system pipe must be removed, inspected,
rectified as necessary and refitted.
4.Remove all traces of oil from exterior of transfer
box.
Take vehicle for short road test.
5.Identify source of leaks and rectify as follows.
Front or rear output seal leaking:-
1.Drain oil and remove leaking output flange.
2.Inspect seal track on flange for surface damage.
If damaged renew component.
3.Remove and discard oil seal.
4.Inspect seal locating bore and remove any sharp
edges which may damage new oil seal.
5.Fit new seal.
6.Fit output flange and all other parts.
7.Add oil to correct level into gearbox
See
SECTION 10, Maintenance, Under vehicle
maintenance
.
Cover plate sealant leaking.
1.Drain oil and remove leaking cover plate.
2.Remove all traces of joint sealant from both joint
faces.
3.Degrease all components and apply a thin film of
Hylomar sealant, to both joint faces.
4.Apply thread sealant to bolts which come into
contact with gearbox oil.
5.Refit cover plate.
CAUTION: Care must be taken not to
overtighten fixings.Leak between main and transfer gearboxes.
1.Site vehicle onto a ramp .
2.Select neutral in transfer box and select 4th gear
in main gearbox.
3.Run engine at 2000 rpm with clutch/drive
engaged.
4.Observe joint between main and transfer boxes.
5.If oil leak is found establish if it is gear oil.
6.If so, leak is originating from transfer box.
7.Check two inner (main/transfer) bolts are oil
tight, as these holes are tapped into main
transfer case.
8.Remove transfer box to inspect mainshaft collar
seal track condition, and front face of transfer
case for porosity
See Repair, Transfer
gearbox
.
9.If these areas require servicing, transfer gearbox
input seal must also be renewed.
CAUTION: Avoid damaging new seal lip
and ensure seal is fitted flush with
machined face. Also ensure new seal is
not damaged when refitting transfer gearbox.
10.If red ATF type oil is seen leaking during
workshop test, investigate main gearbox for
cause of leak.
Detent plug or electrical switch leaks.
1.Detent plugs and electrical switches do not
usually leak. It must be noted that they fit into
open tapped holes in transfer case and therefore
should be considered when looking for source of
leak.

TRANSFER GEARBOX
1
REPAIR TRANSFER GEARBOX
Service repair no - 41.20.25
Remove
The transfer gearbox should be removed from
underneath the vehicle, using a hydraulic hoist and
adaptor plateLRT-99-010.
WARNING: Where use of a transmission
hoist is necessary, it is absolutely
essential to follow the manufacturers'
instructions to ensure safe and effective use of
the equipment.
NOTE: A chassis undertray may be fitted
on some vehicle derivatives to conform to
legal requirements. When under chassis
remove and refit procedures are required, it may
be necessary to remove the undertray
See
CHASSIS AND BODY, Repair, Front undertray
or
See CHASSIS AND BODY, Repair, Rear undertray
.
1.Position vehicle on a ramp.
2.Select LOW range gear and leave vehicle in
neutral.
3.Disconnect battery.
4.Remove front, centre, seat cushion, or cubby
box
See CHASSIS AND BODY, Repair,
Cubby box
.
5.If fitted, disconnect multi-plug from EGR control
unit located on base of seat cushion or cubby
box.
6.Remove 4 screws securing centre access panel
to seat or cubby box base.
7.Release EGR and alarm system diagnostic
connector mounting bracket.
8.Lift up access panel, complete with diagnostic
connector harness, and place aside.
9.Remove breather pipe union from transfer
gearbox high/low cross-shaft housing.
10.Remove retaining clip and disconnect high/low
lever from operating rod.

41TRANSFER GEARBOX
2
REPAIR
11.Remove 3 trim studs and lift up handbrake
gaiter.
12.Remove split pin, clevis pin, washer and
disconnect cable from handbrake lever. Ensure
handbrake is off.
13.Release handbrake outer cable from heelboard.
14.Remove fan cowl
See COOLING SYSTEM,
Repair, Fan cowl
.
15.Raise vehicle on ramp.
16.Drain transfer box oil
See SECTION 10,
Maintenance, Under vehicle maintenance
.
17.Remove intermediate silencer.
See MANIFOLD
AND EXHAUST SYSTEM, Repair,
Intermediate pipe - 90
orSee MANIFOLD
AND EXHAUST SYSTEM, Repair,
Intermediate pipe - 110/130
.
18.Mark rear propeller shaft drive flange and
transmission brake drum for reassembly.
19.Remove 4 nuts, disconnect propeller shaft from
brake drum, and tie aside.
20.Mark front propeller shaft drive flange and
transfer box output flange for reassembly.
21.Remove 4 nuts, disconnect propeller shaft from
transfer box, and tie aside.
22.Remove retaining clip at lower end of pivot arm
and disconnect differential lock control operating
rod.

TRANSFER GEARBOX
3
REPAIR 23.Position 4, 30 mm (1.25 in), spacers between
top of hoist and adaptor plate,LRT-99-010,at
securing points and secure adaptor plate to
hoist.
24.Remove 4 central bolts from transfer box bottom
cover, move hoist into position and secure
adaptor plate to transfer box.
25.Adjust hoist to take weight of transfer box.
26.Remove nut securing transfer box LH mounting
rubber to chassis crossmember.
27.Remove 4 nuts and bolts securing chassis
crossmember to chassis longitudinal.
28.Remove nut securing transfer box RH mounting
rubber to chassis crossmember.
29.Remove 4 nuts and bolts securing chassis
crossmember to chassis longitudinal.
30.With assistance and using a body jack between
chassis longitudinals, jack chassis sufficiently to
enable removal of crossmember.
31.Remove chassis crossmember.
32.Remove 4 bolts from both sides and remove LH
and RH mounting brackets from transfer box.
33.Disconnect electrical leads from differential lock
switch.
34.Move the small cranked lever, for high/low
selector, upward to allow access to adjacent nut
securing transfer box to main gearbox.
35.Position a jack to support main gearbox.
CAUTION: Use a block of wood or hard
rubber pad to protect gearbox.

41TRANSFER GEARBOX
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REPAIR
36.Remove retaining nut, release clamp, and
disconnect speedometer cable from transfer
gearbox.
37.Remove battery earth strap retaining nut, 1 nut
and 4 bolts, securing transfer box to main
gearbox extension case.
38.Remove retaining nut securing earth leads to RH
side of transfer box.
39.Fit three guide studs,LRT-41-009, through
transfer box bolt holes to support it during
removal.
40.Lower hoist and withdraw transfer box from main
gearbox.
41.Remove transfer box.Refit
42.Ensure joint faces of transfer box and main
gearbox are clean and guide studs,LRT-41-009,
are fitted to extension case.
43.Lubricate oil seal in joint face of transfer box.
44.Secure transfer box to adaptor plate on lifting
hoist and raise hoist until transfer box can be
located over guide studs.
45.Remove guide studs, fit battery earth strap, and
secure transfer box to main gearbox extension
case. Tighten fixings to
45 Nm (33 lbf/ft).
46.Fit electrical leads to differential lock switch.
47.Raise hoist and remove wooden block
supporting main gearbox.
48.Secure LH and RH mounting brackets to
gearbox and tighten fixings to
55 Nm (41 lbf/ft).
49.With assistance and using a body jack between
chassis longitudinals, jack chassis sufficiently to
enable fitment of crossmember.
50.Position chassis crossmember and locate over
fixing studs of LH and RH gearbox mounting
rubbers .
51.Align crossmember and secure to chassis with 4
nuts and bolts on each side.
NOTE: Fit battery earth strap retaining clip
to LH top bolt.
52.Remove body jack.
53.Fit retaining nut to LH and RH mounting rubbers.
Tighten to
21 Nm (15 lbf/ft).
54.Remove 4 bolts securing hoist adaptor plate to
transfer box bottom cover.
55.Lower hoist and move aside.
56.Clean threads of the 4 bolts, coat with Loctite
290, and fit to transfer box bottom cover. Tighten
to
25 Nm (18 lbf/ft).
57.Fit earth leads to RH side of transfer box.
58.Connect differential lock control operating rod to
pivot arm.
59.Fit speedometer cable to transfer box.
60.Fit front and rear propeller shafts to transfer box.
Tighten nuts to
47 Nm (33 lbf/ft).
61.Fit intermediate silencer.See MANIFOLD AND
EXHAUST SYSTEM, Repair, Intermediate
silencer - 90; Refit
orSee MANIFOLD AND
EXHAUST SYSTEM, Repair, Intermediate
pipe - 110/130; Refit
.
62.Refill transfer box with recommended oil
See
SECTION 10, Maintenance, Under vehicle
maintenance

TRANSFER GEARBOX
5
REPAIR REV: 05/9963.Feed transmission brake cable through heel
board. Ensure cable grommet is correctly
located.
NOTE: Apply a soap solution to aid fitment
of cable.
64.Lower vehicle ramp.
65.Connect cable clevis to handbrake lever and fit
handbrake gaiter.
66.Connect high/low lever to operating rod.
67.Fit breather pipe banjo union to high/low
cross-shaft housing.
68.Fit centre access panel to seat base. If fitted,
secure EGR and alarm system diagnostic
connector mounting bracket to front of access
panel.
69.If fitted, reconnect multi-plug to EGR control unit
on base of centre seat cushion or cubby box.
70.Fit seat cushion or cubby box
See CHASSIS
AND BODY, Repair, Cubby box
.
71.Reconnect battery.
72.Check operation of handbrake and adjust as
necessary
See MAINTENANCE , Handbrake
cable
.