wheel LAND ROVER DISCOVERY 1995 Repair Manual

TRANSFER GEARBOX
1
DESCRIPTION AND OPERATION LT230T TRANSFER BOX
The LT230T transfer box 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.
A shiftlock device is fitted in some territories, it is used
as a park facility and prevents accidental gear
disengagement when the ignition is switched off. An
audible neutral alarm is also fitted. This alerts the
driver when parking to move the gear lever to the high
or low position.

44AUTOMATIC GEARBOX
2
DESCRIPTION AND OPERATION Power flow
1st gear D selected
With D selected 1st gear engaged, clutches 4 and 11 are operative. The front planet gear carrier of gear set 9 is
locked against the housing through freewheel 15 when the engine is pulling but freewheels when the vehicle is
coasting. Epicyclic gear set 10 rotates as a solid unit with the front planet gear carrier. In selector position 1 with
1st gear engaged, clutch 8 operates to prevent the loss of drive on the overrun through freewheel 15, to provide
engine braking.
2nd gear D selected
Clutches 4, 6, 7 and 11 are engaged. Freewheel 15 overruns, the hollow shaft with the sun wheel of epicyclic gear
set 9 is locked. Epicyclic gear set 10 also rotates as a solid unit.

ZF
3
DESCRIPTION AND OPERATION 3rd gear D selected
Clutches 4, 5, 7 and 11 are engaged. Freewheel 15 and 16 are overrun. Epicyclic gear set 9 and 10 rotate as a
solid unit at a ratio of 1:1.
4th gear D selected
Clutches 4, 5, 7 and 12 are engaged. Freewheel 14, 15 and 16 are overrun. Epicyclic gear set 9 rotates as a solid
unit. The hollow shaft with the sun wheel of epicyclic gear set 10 is locked.
Above a predetermined road speed, clutch 2 locks the gearbox power input direct to the engine, by-passing the
torque converter.

44AUTOMATIC GEARBOX
8
FAULT DIAGNOSIS 1. Freewheel and fourth gear assembly

44AUTOMATIC GEARBOX
10
FAULT DIAGNOSIS FAULT SYMPTOMS
SYMPTOM 1 - Intermittent drive and high pitched
noise
FAULT - Low fluid level or restricted filter
SYMPTOM 2 - No drive in reverse
Select 'D'
ú No drive
FAULT - Continue with Symptom 3
ú Drives forward
FAULT - Reverse gear interlock valve
seized
Select '1'
ú No engine braking
FAULT - Clutch brake 3
SYMPTOM 3 - No drive from rest with 'D' selected
Select '1'
ú Vehicle drives
FAULT - No 2 freewheel
ú No drive
Carry out main line pressure check
ú Normal pressure
FAULT - Clutch A
ú No pressure
FAULT - Blocked filter or pump failure
ú Low pressure
FAULT - Restricted filter or sticking primary
regulator
SYMPTOM 4 - Slip in all forward gears
Carry out main line pressure check
ú No pressure
FAULT - Blocked filter or pump failure
ú Low pressure
FAULT - Restricted filter or sticking primary
regulator
ú Normal pressure
FAULT - Clutch 'A'SYMPTOM 5 - Harsh engagement 'N' to 'D'
Check engine idle speed
Carry out main line pressure check
ú High pressure
FAULT - Primary regulator stuck
ú Normal pressure
FAULT - Clutch 'A' or damper for clutch'A'
SYMPTOM 6 - Fierce shift or flare 1st to 2nd shift
Check engine idle speed
Carry out mainline pressure check
ú High pressure
FAULT - Continue with symptom 5
ú Normal pressure
FAULT - Modulator valve or dampers for
clutch brake CB1 and/or clutch brake CB2
FAULT - Clutch brake CB1 and/or clutch
brake CB2
SYMPTOM 7 - Fierce shift or flare 2nd to 3rd
Carry out mainline pressure check
ú High pressure
FAULT - Continue with symptom 5
ú Normal pressure
FAULT - Modulator valve or clutch 'B'
damper
FAULT - Clutch 'B'
SYMPTOM 8 - No 3rd gear
FAULT - 2-3 shift valve
FAULT - Clutch 'B'
SYMPTOM 9 - No 4th gear 'D' selected
FAULT - 4th to 3rd downshift valve stuck or
3rd to 4th upshift valve stuck
FAULT - Clutch brake 4

44AUTOMATIC GEARBOX
6
REPAIR 13.Remove starter.
14.Working through starter aperture note position of
torque converter flexible drive plate to facilitate
refitting.
15.Remove the four torque convertor to flexible
drive securing bolts, rotating engine to gain
access to each individual bolt.
16.Raise vehicle on four post ramp [hoist].
17.Drain lubrication oil from transfer and main
gearboxes.
18.Disconnect speedometer cable from transfer
gearbox and disconnect associated clipping.
19.Remove rear propeller shaft.
See PROPELLER
SHAFTS, Overhaul, Flexible Coupling
20.Disconnect front propeller shaft at transfer
gearbox and tie to one side.
21.Remove exhaust front pipe.
22.Remove bolts securing front and centre silencer
mounting brackets and tie silencer to one side.
23.Disconnect oil cooler pipes from gearbox.
24.Blank off pipes and union connections.
25.Remove bolt securing retaining bracket to sump
and move cooler pipes aside.
26.Disconnect selector cable from lever on side of
gearbox.
27.Disconnect inhibitor switch multi-plug.
28.Disconnect park brake cable from linkage to park
brake lever.
29.Disconnect electrical connections from
differential lock switch on transfer gearbox.
30.Remove two lower bolts from transfer gearbox
input bearing support plate.
31.Assemble approved support cradle to
transmission hoist.32.Raise hoist and secure cradle to transfer
gearbox input bearing support plate using bolts
removed.
33.Disconnect gearbox mounting brackets from
chassis cross member.
34.Remove chassis cross member.
35.Lower transmission sufficiently to allow access
to items attached to top of gearbox.
36.Remove left hand gearbox mounting bracket
assembly.
37.Remove ties from breather pipes and harness.
38.Remove nut securing gearbox oil filler/dip stick
tube to bell housing.
39.Release union nut at gearbox sump and remove
filler/dipstick tube. Fit blanking plugs.
40.Support engine using a wooden block with a
suitable ramp [hoist] jack.
41.Remove nut securing kick down cable bracket to
bell housing.
42.Remove two bolts securing top of bell housing to
flywheel housing.
43.Remove nuts securing bell housing to flywheel
housing and withdraw transmission assembly
from engine.
44.Fit a suitable torque converter retaining strap to
the bell housing.
45.Remove hoist and transmission from under
vehicle.
46.Fit lifting eyes to transmission.
47.Using suitable chains and lifting tackle take
weight of transmission assembly.
48.Remove bolts securing transmission cradle to
transfer box and withdraw hoist complete with
cradle.
49.Refit bolts to cover plate.

ZF
7
REPAIR Accessories removal/fitting
If fitting a replacement transmission assembly to the
vehicle, remove the following items from the existing
assembly and fit to the replacement.
CAUTION: It is important to remove the
spacer from the extension shaft and fit
onto the replacement unit.
50.Breather pipe union and washers from main
gearbox.
51.Breather pipe, union and washers from transfer
gearbox.
52.Main gearbox selector lever.
53.RH mounting bracket assembly.
54.Oil cooler pipe unions.
55.Fit blanks to all apertures where unions have
been removed and blank off pipe ends.
Refit
1.Fit transmission to cradle and hoist.
2.Locate hoist under vehicle and remove torque
convertor retaining strap.
3.Ensure low range gear is engaged.
4.Apply approved sealant to bell housing face.
5.Carefully raise assembly, align bell housing with
flywheel housing and bring mating faces
together.
6.Fit nuts and bolts to secure transmission to
engine.
7.Locate electrical wiring and breather pipes to
position.
8.Secure kick down cable clip to bell housing.
9.Raise hoist sufficiently to take weight.
10.Remove block and jack from engine sump.
11.Fit filler/dipstick tube to gearbox sump and
secure bracket to bell housing.
12.Apply Loctite to torque convertor bolts
13.Working through starter aperture refit the four
torque convertor to flexible drive securing bolts,
rotating crankshaft to gain access to bolt
locations.
14.Refit starter and heatshield.
15.Secure breather pipes and harness with ties.
16.Fit left hand mounting bracket assembly to
gearbox.
17.Raise transmission and support with a suitable
ramp [hoist] jack.
18.Remove two bolts securing transmission to
cradle, lower hoist and remove from under
vehicle.
19.Apply Loctite to above bolts and fit to transfer
gearbox input bearing support plate.
20.Fit chassis cross member.21.Secure gearbox mounting brackets to chassis
cross member.
22.Remove ramp [hoist] jack.
23.Connect electrical leads to differential lock
switch.
24.Connect inhibitor switch multi-plug.
25.Connect selector cable to lever on side of
gearbox.
26.Connect oil cooler pipes to gearbox and secure
retaining bracket to gearbox sump.
27.Secure silencer to chassis and refit exhaust front
pipe.
28.Refit front propeller shaft to transfer gearbox.
29.Refit rear propeller shaft.
See PROPELLER
SHAFTS, Overhaul, Flexible Coupling
30.Connect speedometer cable to transfer gearbox.
31.Refill transfer gearbox with correct grade of
lubricating oil.
See LUBRICANTS, FLUIDS
AND CAPACITIES, Information,
Recommended Lubricants and Fluids
32.Lower ramp [hoist] to ground level.
33.Reconnect turbo-charger hose to inter-cooler.
34.Reconnect top hose to radiator.
35.Refill cooling system with correct mixture of
coolant.
See LUBRICANTS, FLUIDS AND
CAPACITIES, Information, Recommended
Lubricants and Fluids
36.Reconnect kick down cable to fuel injection
pump.
37.Secure breather pipe clip to rear of cylinder
head.
38.Engage harness with clips along top of
bulkhead.
39.On left hand drive vehicles only, connect
multi-plug to top of brake fluid reservoir.
40.Refit insulation pad to rocker cover and inlet
manifold, secure with oil filler cap.
41.Refit gaiter and knob to transfer gear lever.
42.Select high range gear.
43.Reconnect battery terminals.
44.Refill main gearbox with correct grade of
lubricating oil.
See LUBRICANTS, FLUIDS
AND CAPACITIES, Information,
Recommended Lubricants and Fluids

44AUTOMATIC GEARBOX
16
REPAIR GOVERNOR HUB
Service repair no - 44.22.04
Remove
1.Remove transfer box.
See TRANSFER
GEARBOX, Repair, LT230T Transfer Gearbox
2.Remove transfer gear selector housing.
3.Loosen nine bolts holding extension housing.
4.Remove extension housing ensuring that seal is
not damaged, discard gasket.
5.Remove extension shaft and retaining bolt with
'O' ring. If Tdi vehicle remove spacer.
6.Remove governor assembly with parking wheel.
7.Remove two screws holding governor housing.
8.Remove two bolts, remove parking wheel.
Discard governor hub.
9.Remove security clip and counter-weight.
10.Remove 'O' ring from output shaft and discard.
11.Remove three seal rings from 'F' clutch housing
shaft.
12.Inspect all parts for damage or wear, replace if
necessary.
Refit
13.Fit counterweight and security clip into new
governor hub.14.Secure governor housing to governor hub.
Tighten to
10Nm.
15.Fit parking wheel to governor hub. Tighten to10
Nm.
16.Fit three new seal rings onto F clutch housing
shaft, fit 'O' ring onto output shaft.
NOTE: To aid fitting of 'O' ring apply
petroleum jelly.
17.Push governor assembly and parking wheel onto
output shaft until seated.
NOTE: Apply petroleum jelly to 'O' ring.
Ensure seal rings are snapped together
and seated.
18.Fit new gasket to rear of gearbox. Fit extension
housing, avoid damaging seal.
19.Fit extension shaft,and spacer if Tdi, apply
Loctite 270 to retaining bolt. Using a new 'O'
ring, tighten bolt to
42 Nm.
20.Tighten nine extension housing nine bolts to23
Nm.
21.Fit transfer gear selector housing, tighten three
bolts to
25 Nm.
22.Refit transfer box.

ZF
17
REPAIR PARKING PAWL MECHANISM
Service repair no - 44.28.07
Remove
1.Remove transfer box.
See TRANSFER
GEARBOX, Repair, LT230T Transfer Gearbox
2.Remove transfer gear selector housing.
3.Loosen nine bolts holding extension housing.
4.Remove extension housing ensuring that seal is
not damaged, discard gasket.
5.Remove extension shaft and retaining bolt with
'O' ring. If Tdi vehicle, remove spacer.
6.Remove governor assembly with parking wheel.
7.Remove guide plate bolt.
8.Remove plate and guide plate from gearbox
case.
9.Remove pin, pawl and spring.
CAUTION: When removing assembly.
Avoid damaging parts which could weaken
spring tension.
10.Inspect all parts for wear or damage. Replace if
necessary.
Refit
11.Fit pin and leg spring, locate spring correctly.
12.Fit pawl to pin. Locate spring leg into hole in
pawl to create tension in spring.
13.Fit plate and guide plate. Tighten to
10 Nm.
14.Push governor assembly with parking wheel
onto output shaft until seated.
NOTE: Apply petroleum jelly to 'O' ring.
Ensure seal rings are snapped together
and seated.
15.Fit new gasket to rear of gearbox. Fit extension
housing, taking care not to damage seal or
assembly.
16.Fit extension shaft with spacer if Tdi and
retaining bolt with new 'O' ring.
17.Fit extension housing, tighten nine bolts to
23Nm.
18.Fit transfer gear selector housing, tighten three
bolts to
25 Nm.
19.Refit transfer box.

44AUTOMATIC GEARBOX
2
SPECIFICATIONS, TORQUE ZF GEARBOX DATA
Axial end float 0.2 to 0.4 mm.
From torque converter boss to torque converter
housing face 50 mm
Freewheel cage assembly to ring gear; minimum
clearance 0.1 mm
Output shaft above cylinder F assembly; dimension
10.00 mm
A cylinder protrusion above gearbox front face not
more than 8.5 mm