1995 LAND ROVER DISCOVERY engine

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.

ZF
1
FAULT DIAGNOSIS ZF AUTOMATIC GEARBOX
Before referring to fault symptoms, carry out initial
static checks first:
INITIAL STATIC CHECKS
Check start positions 'P' & 'N' only........................................................
Reverse lights 'R' only..................................................................
Gear engagements N-D,N-3,N-2,N-1,N-R..........................................................
Full throttle Engine switched off, check full travel at engine and at.......................................................................
pedal.
Oil level 'N' selected, engine running at normal running............................................................................
temperature.
Pressure test
2000 rev/min 10±0.3 bar, 150±5 lbf/in
2....................................................................
Idle pressure 6.9±0.3 bar, 100±5 lbf/in2at 665 to 735 rev/min. ....................................................................
To fit pressure gauge
Service tools:
See Service tools, Automatic
Gearbox
0 to 20 bar, 0 to 300 lbf/in2Pressure gauge.
Flexible hose adaptor.
1.Site vehicle on a ramp [hoist].
2.From under gearbox, remove socket head plug
(located 10cm from oil pipe) Fit hose adaptor
LST502-1.
3.Fit hose to adaptor.
4.Fit gauge 18G502A to hose and route into
vehicle, ensuring hose is clear of rotating parts
and exhaust pipes.
5.Carry out road test.
See Road Test Procedure
Remove pressure gauge
6.Reverse removal procedure.

44AUTOMATIC GEARBOX
2
FAULT DIAGNOSIS ROAD TEST PROCEDURE
Follow the procedure given commencing each test,
from a standing start, on a level road, in good weather
conditions.
ROADTEST 1 = CHECKS 1-2-3-4-5-6-7-8
D SELECTED KICKDOWN START FROM REST
CHECK 1
Check for clutch squeal and slip. Check pressure is
150lbf/in
2
CHECK 2
Check 1st to 2nd upshift speed and quality. Pressure
should fall to 120 lbf/in
2.
CHECK 3
Check 2nd-3rd upshift speed and quality. Pressure
should fall to 100 lbf/in
2
CHECK 4
Release throttle to allow simultaneous engagement
4th + DDC. Check shift quality and engine rpm drop of
approximately 500 rpm.
CHECK 5
To proceed to Check 5 release throttle and check
drop out speed of direct drive clutch to 4th.
CHECK 6
Check down shift speed and quality 4th to 3rd.
NOTE: This shift is usually very smooth
and difficult to detect.
CHECK 7
Check downshift speed and quality 3rd to 2nd.
CHECK 8
Check downshift speed and quality 2nd to 1st. Also
difficult to detect.
END OF ROADTEST 1ROADTEST 2 CHECKS = 9-10-11
D SELECTED FROM REST
FULL THROTTLE START
CHECK 9
Check 1st-2nd upshift speed and quality.
CHECK 10
Check 2nd 3rd upshift speed and quality.
CHECK 11
Check 3rd 4th and direct drive clutch upshift speed
and quality.
NOTE: 4th and the direct drive clutch
engage simultaneously.
END OF ROADTEST 2

ZF
3
FAULT DIAGNOSIS ROADTEST 3 = CHECKS
12-13-14-15-16-17-18-19-20-21-22-23
D SELECTED FROM REST
LIGHT THROTTLE START
CHECK 12
Check 1st 2nd upshift speed and quality.
CHECK 13
Check 2nd 3rd upshift speed and quality.
CHECK 14
Check 3rd 4th upshift speed and quality.
NOTE: This shift is usually very difficult to
detect but can be confirmed by a 200 rpm
drop in engine speed.
CHECK 15
Check speed and quality of shift into direct drive
clutch, confirmed by 300 rpm drop in engine speed.
NOTE: An intermediate throttle position
engagement of 4th and the direct drive
clutch, which is indicated by a fall of
500rpm in engine speed.
CHECK 16
At approximately 88 kph (55 mph) depress throttle to
kickdown - gearbox should change down to 2nd -
release throttle to re-engage 4th direct drive clutch
continue to accelerate gently.
CHECK 17
At approximately 128 kph (80 mph) depress throttle to
kickdown - gearbox should change down to 3rd -
release throttle to re-engage 4th direct drive clutch
and continue to accelerate gently.CHECK 18
At approximately 138 kph (85 mph) select 3rd,
gearbox should change immediately down to 3rd.
Release throttle.
CHECK 19
De-accelerate to approximately 47 kph (30 mph)
depress throttle to kickdown - geabox should
downshift to 1st gear, continue accelerating at full
throttle until 3rd gear is attained. To do this you will
have repeated check 2 of Test 1.
CHECK 20
At 128 kph (80 mph) select 2nd no downshift should
occur. Release throttle.
CHECK 21
At 104 kph (65 mph) an automatic downshift into 2nd
gear should occur. Continue to de-accelerate.
CHECK 22
At 88 kph (55 mph) select 1st. No downshift should
occur. Continue to de-accelerate.
CHECK 23
With 1 selected 2nd gear engaged continue to
de-accelerate and at 45 kph (28 mph) the box should
automatically downshift to 1st gear after which no
upshifts will occur in this selector position.
END OF ROADTEST

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

ZF
11
FAULT DIAGNOSIS SYMPTOM 10 - None or harsh engagement of
direct drive clutch
NOTE: The direct drive clutch will only
engage if 4th gear is engaged at 40 to 45
mph.
Carry out road test pressure check with gauge
connected to torque converter.
ú Normal pressure
FAULT - Failed direct drive clutch
ú Pressures correct but remains high
FAULTS POSSIBLE -
Direct drive clutch and torque converter
control valve stuck
Hysteresis valve stuck
Direct drive clutch control valve stuck
SYMPTOM 11 - Direct drive clutch shift point
incorrect or at low speed
NOTE: Direct drive clutch engagement at
low speed will cause vibration in the
torque converter
Carry out mainline and torque converter pressure
check
ú Normal pressure
FAULT - Governor valve sticking
ú Low or incorrect pressure
FAULTS POSSIBLE -
Direct drive clutch and torque converter
control valve sticking.
Hysteresis valve stuck.
Direct drive clutch control valve stuck.
SYMPTOM 12 - Drives in 'D' but immediately
upshifts to 3rd
FAULT - 2nd to 3rd shift valve stuck.
SYMPTOM 13 - With 'D' selected vehicle starts in
2nd
FAULTS POSSIBLE -
1st and 2nd shift valve stuck.
Governor sleeve sticking.
SYMPTOM 14 - With 'D' selected vehicle starts in
3rd
FAULTS POSSIBLE -
1st to 2nd and 2nd to 3rd shift valves stuck.
Governor sleeve sticking.SYMPTOM 15 - No kickdown 4th to 3rd
FAULT - 4th to 3rd kickdown valve stuck.
SYMPTOM 16 - Upshifts/downshifts and kickdown
shifts at incorrect road speeds
Check throttle kickdown cable adjustment
Carry out main line pressure check
ú Normal pressure
FAULT - Governor valve sticking
ú Incorrect pressure
FAULTS POSSIBLE -
Incorrect throttle valve adjustment
Primary regulator sticking
SYMPTOM 17 - No upshifts at light throttle
FAULTS POSSIBLE
Governor valve sticking
Shift valves sticking
SYMPTOM 18 - No engine braking '3' selected 3rd
gear
FAULT - Clutch 'C'
SYMPTOM 19 - Delayed or no downshift occurs
when making a manual selection from '3' to '2'
FAULTS POSSIBLE -
2nd and 3rd upshift valve sticking.
Governor valve sticking.
'2' Position interlock valve sticking.
SYMPTOM 20 - At speeds below 28 mph when
making a manual selection from '2' to '1',
downshift is delayed or does not occur
FAULTS POSSIBLE -
Governor sticking.
1st to 2nd shift valve sticking.
'1' Position interlock valve sticking.
SYMPTOM 21 - '1' Selected 1st gear no engine
braking
FAULT - Clutch brake 3
SYMPTOM 22 - '2' Selected 2nd gear no engine
braking
FAULT - Clutch brake 1
SYMPTOM 23 - Vehicle drives forward in 'N'
FAULT - Clutch 'A' stuck

ZF
1
REPAIR LT230T TRANSFER GEARBOX WITH AUTOMATIC
GEARBOX ASSEMBLY - V8i
Service repair no - 44.20.04
Removal from V8i engine
The assembled transfer gearbox, automatic gearbox
and torque converter is removed from underneath the
vehicle. Use a transmission hoist with an adaptor
plate for securing the assembly to the hoist. The
adaptor can be manufactured locally to the drawing
below or purchased from:- Straight Set Engineering,
England. Tel.01909 480055
WARNING: When using a transmission
hoist it is essential to follow the hoist
manufacturer's instructions.