ZF Automatic Transmissions Service Manual
The torque converter acts in all four forward gears and in reverse. The converter lock-up clutch closes in 4th gear at
a point depending on road speed and accelerator position; engine power is then transmitted by purely mechanical
means.
A low-loss oil pump in the front of the transmission housing supplies the converter, the automatic gear shift and the
lubrication circuit; oil is drawn from a sump in the bottom of the gear train housing through a filter. The pump drive
gear is keyed to the converter impeller hub and therefore turns when the engine is running, thereby pressurizing the
oil.
Selected ratios
Di, 31, 21
1.1.2 Four-speed Epicychc Gear Train
The torque converter drives a mechanical epicyclic gear train providing four forward ratios and reverse. Individual ra-
tios are obtained by coupling togetherthevarious parts of the geartrain by means of hydraulically actuated multi-disc
clutches and brakes; built in freewheels permit gear shifts without any interruption of the power flow. Operation of the
clutches and gear sets is described
in sub-section 1.1.3.
Each epicyclic (or planetary) gear set comprises a central, sungear, an annulus and a planetary carrier which supports
four small planet gears or pinions. Two gear sets are used in this transmission. A compound gear set comprising front
annulus and planet carrier, rear annulus and planet carrier and a common sungear transmits the drive
in all gears ex- cept REVERSE; a single planetary carrier, annulus and sungear transmits the fourth gear drive. The table below shows
the resulting clutch operation
in the selected gear ratios.
Resulting clutch operation
A Clutch drives annulus clockwise
E Clutch
& OWC drives output shaft clockwise
D2,32,22
D3,33, 23
04
R
Park, Neutral
A Clutch drives annulus clockwise
C1 Clutch holds sungear against anti-clockwise
C Clutch
& OWC holds sungear against anti-clockwise
A Clutch drives annulus clockwise
B Clutch drives sungear clockwise
C Clutch
& OWC holds sungear against anti-clockwise
A Clutch drives annulus clockwise
B Clutch drives sungear clockwise
C Clutch & OWC holds sungear against anti-clockwise
B Clutch drives sungear clockwise
D Clutch holds carrier against clockwise
E Clutch
& OWC drives output shaft anti-clockwise
E Clutch
& OWC applied (hydraulics)
OWC = one way clutch
2 Issue 1 August 1994
ZF Automatic Transmissions Service Manual
Problem Possible Cause
1.3.6 Fault Finding Chart
Action
Converter
Stall speed too low
Stall speed too
high and keeps
rising
Acceleration below specification
Top speed below specification
Position 'P'- Park
Will not move out of Park
Does not engage Park
Does not hold
Starter motor does not operate
Position 'R- Reverse
No reverse gear or severely
delayed engagement
High pitched squeaking noise Stator freewheel
faulty allowing
stator to revolve
Engine out of tune
Transmission slip.
Engine out of tune
Torque converter freewheel faulty
allowing stator to revolve.
Engine out of tune.
Torque converter freewheel seized.
Engine out of tune.
Gearshift interlock failure
Parking pawl mechanism sticking
Check cable adjustment
Parking pawl mechanism damaged
Check cable adjustment
Starter
inhibit switch faulty.
Faulty selector lever.
Position
'P' or 'N' not selected.
Check cable adjustment
Dirty oil filter.
Jammed governor.
Jammed reverse inhibit valve.
Low oil level.
'B' clutch destroyed (also no 3rd
gear
in Drive).
'D' clutch destroyed.
'E' clutch destroyed (no engine
braking
in 2nd & 3rd gears.
Reverse gear safety valve faulty. Renew
torque converter
Check engine tune.
Check oil level, check mechanical
failure, renew transmission as
necessary.
Renew torque converter.
Check engine tune.
Renew torque converter.
Check engine tune.
Rectify. Renew fuse, check circuits,
renew relay and solenoid.
Renew park pawl components:
connecting bar, pawl
pin, tension
spring, guide piece
& guide sheet
Adjust cable as necessary.
Replace park pawl components
Adjust cable as necessary.
Replace switch.
Replace lever.
Select 'P'
or 'N'.
Adjust cable as necessary.
Renew oil filter.
Replace governor.
Replace valve block.
Check oil.
Service
/ renew transmission.
Service
/ renew transmission.
Service
/ renew transmission.
Service
/ renew valve block.
Issue 1 August 1994 34
1.3.6 Fault Finding Chart (continued)
Problem Possible Cause
slipping or shaking from start in
'everse gear
Strong jerk, or distant double
erk, when engaging positions
P
-R', or 'N-R' (below 1500RPM
tngine speed)
'B','E or 'D' clutch defective
Damper
'6' defective (will give the
same symptoms when changing
from 2nd to 3rd gears
Action
Service 1 renew transmission.
Service
1 renew valve block
qeverse lamp does not illuminate Starter inhibit switch faulty.
bulbs, fuses and cables
'unctioning correctly) Faulty selector lever.
io drive or severe delay. Renew
switch.
Renew lever.
Slipping or shaking during initial Position
'R' not
selected.
'orward movement
Strong jerk 'N
-D' (below 1500
3PM engine speed) Select
'R'.
Sear change functions
faulty (in c'
Zhange 1st to 2nd 12nd to 1st Governor dirty.
Shift valve 1-2 sticking.
Zhange 1st to
2nd
Renew governor.
Renew valve block.
Zhange 2nd to 3rd
13rd to 2nd
Governor dirty.
Shift valve 3
-4 sticking.
:hange 2nd to 3rd
Zhange 3rd to
4th I 4th to 3rd Renew
governor.
Renew valve block.
Sudden shifts
Jehicle starts in 2nd gear Governor sleeve sticking.
Shift valve 1
-2 sticking.
Governor sleeve sticking.
Shift valves 1
-2 and 2-3 sticking.
Jehicle starts in 3rd gear Renew
governor.
Renew valve block.
Renew governor.
Service
I renew valve block.
Searbox changes 1st to 3rd
Uo shifts Dirty
oil filter.
Oil level incorrect.
'A' clutch defective.
'D' clutch one
-way clutch faulty.
'A' clutch damaged
'A' clutch faulty.
'A' clutch damper faulty.
Id or warm state)
If there is no debris in sump, renew the
oil filter and oil;
if debris is present in
the sump, renew the transmission.
Check oil level.
Service
I renew transmission.
Service
1 renew transmission.
Service
I renew transmision
Service
1 renew transmission.
Service
/ renew valve block.
Brake
'Cl' and 1 or 'C' faulty I Service / renew transmission
Governor dirty.
I Renew governor.
Shift valve 2-3 sticking.
'B' clutch faultv
Renew valve block.
Service
I renew transmission
Dampers sticking
I Service I renew valve block
Shift valve 2
-3 sticking I Service 1 renew valve block
Governor sticking.
Dampers sticking. Change
governor.
Service
I renew valve block
Issue 1 August 1994 35
ZF Automatic Transmissions Service Manual
Problem Possible Cause
1.3.6 Fault Finding Chart (continued)
Action
>hange points at incorrect
;peeds
3eneral
Kick-down' cable sticking
Voisy and no drive after a long
ourney
dery noisy and no drive
3il leaks
3il dripping from the bell
iousing
-eakage between transmission
and oil sump
-eakage between intermediate
date and main housing
:especially at pump pressure
Doint)
3il leak at output
-eakage from cooler pipes
-eakage between main housing
jnd tail housing
3il leak from 'kick-down' cable at
:ransmission end 'Lock
-up'
safety valve sticking.
'Kick
-down' cable setting incorrect.
No 4th gear.
Governor pressure incorrect.
Nipple in throttle cam is worn.
Too much friction in sleeve of
'kick
-down' cable.
Throttle pressure piston sticking.
Oil filter on valve block faulty
Drive plate is worn or broken
Seal ring in pump housing
damaged.
Defective pump 0
-ring.
Pump housing porous.
Converter leaking from welded
seam.
Bolts incorrectly
torqued.
Sump gasket damaged.
Bell housing bolts loose.
Gasket damaged.
Output oil seal damaged
Loose connections.
Pipes damaged.
Cooler leaks.
Loose bolts.
Gasket damaged.
'0' ring connection damaged Service
/ renew valve
block / governor.
Adjust setting.
Check cable adjustment, service
/
renew valve block / governor.
Service
1 renew valve block I governor.
Replace cable.
Replace cable
Service
/ renew valve block.
If there is no burnt lining in the sump,
renew the filter and oil. If debris is
present, renew the transmission.
Renew the drive plate
Renew seal.
Renew
@ring.
Renew pump housing.
Renew converter.
Tighten bolts to specified torque.
Renew sump gasket.
Tighten bolts to specified torque.
Renew gasket.
Renew seal
Tighten connections.
Renew pipes.
Renew cooler.
Tighten bolts.
Renew gasket.
Renew
'0' ring or complete cable
issue 1 August 1994 37
1.3.6 Fault Finding Chart (continued)
Problem
.oss of oil through breather
3il leak at intermediate plate
-eakage between gearbox and
2xtension housing
Uoises
iigh pitched squeaking noise,
jependant on engine RPM, in all
jears, when oil is warm and
accompanied by intermittent
hive after a long journey
iigh pitched noise in all
Dositions, especially if oil is cold.
Sucking noise from pump.
dery noisy in 'lock-up'
rorsional vibrations from engine
Nhen in 'lock-up'
-oud noisewhen converter
:lutch engages
Engine vibrations when
:onverter clutch engaged
Possible Cause
Oil level too high.
Incorrect oil.
Breather blocked.
No breather cap.
'0' ring breather damaged.
Securing clip faulty.
Blanking plug loose
Fastening screws loose.
Gasket faulty.
Dirty filter
Low oil level.
Filter not sealing.
Leaking valve block.
Filter damaged.
Torsion damper faulty
Engine
RPM is too low, 'lock-up'
shift point incorrect
Torsion damper defective
Change point too low
Action ___ Check level.
Remove transmission, ensuring that
it
is drained (including torque converter,
oil cooler and pipes).
Change breather, check for foul
condition
of foam insulation pad.
Fit cap or renew breather.
Remove tail housing and replace
'0'
ring.
Renew clip.
Tighten plugs. Renew sealing washers.
Tighten screws to specified torque.
Renew gasket.
If there is no debris in the sump, renew
the filter and oil.
If debris is present,
renew the transmission.
Top-up as necessary.
Check
I renew 0-ring.
Service
/ renew valve block.
Check filter.
Renew torque converter
Service
I renew valve block
Renew converter
Check valve block ~~
Issue 1 August 1994 38
ZF Automatic Transmissions Service Manual
The torque converter acts in all four forward gears and in reverse. The converter lock-up clutch closes in 4th gear at
a point depending on road speed and accelerator position; engine power is then transmitted
by purely mechanical
means.
A low
-loss oil pump in the front of the transmission housing supplies the converter, the automatic gear shift and the
lubrication circuit; oil is drawn from a sump in the bottom of the gear train housing through a filter. The pump drive
gear is keyed to the converter impeller hub and therefore turns when the engine is running, thereby pressurizing the
oil.
2.1.2 Four-speed Epicyclic Gear Train
The torque converter drives a mechanical epicyclic gear train providing four forward ratios and reverse. Individual ra-
tios are obtained by coupling together the various parts of the gear train by means of solenoid-operated, hydraulically
actuated multi-disc clutches and brakes; built in freewheels permit gear shifts without any interruption of the power
flow.
For information on the operation of the solenoids, clutches, brakes and freewheels, refer to the table below and the
schematic diagrams shown overleaf.
A parking lock pawl is provided at the rear of the gear train, operating on a toothed wheel attached to the output shaft;
the parking lock is operated from the selector (position
'P) by actuator rod.
An electro
-magnetic sensor detects output shaft revolutions by means of a toothed disc attached to the shaft; one rev- olution of the shaft is equal to 36 pulses. The electrical signal from the sensor is passed, via a screened cable, to the
TCM.
R
Park,
Neutral
Solenoid ~
MV2
MVI, MV2
MVI, MV3
MV2
-
MV2
OWC
= one way clutch
Resulting clutch operation
A Clutch drives annulus clockwise
D Clutch OWC holds F carrier against shaft clockwise
E Clutch & OWC drives output shaft clockwise
A Clutch drives annulus clockwise
C1 Clutch holds sungear against anti-clockwise
C Clutch
& OWC holds sungear against anti-clockwise
A Clutch drives annulus clockwise
B Clutch drives sungear clockwise
C Clutch
& OWC holds sungear against anti-clockwise
A Clutch drives annulus clockwise
B Clutch drives sungear clockwise
C Clutch
& OWC holds sungear against anti-clockwise
B Clutch drives sungear clockwise
D Clutch holds carrier against clockwise
E Clutch & OWC drives output shaft anti-clockwise
E Clutch & OWC applied (hydraulics)
40
Issue 1 August 1994
ZF Automatic Transmissions Service Manual
2.2 HYDRAULIC CIRCUIT DIAGRAMS
Component Engagement
Key
To Hydraulic Diagrams (commencing on page 52)
1. 2.
3. 4.
5. 6.
7.
8. 9. 10. 11. 12. 13.
14. 15. 16.
17.
18.
Oil pump Sump
Torque converter
Olil cooler
Clutch 'A' damper
Clutch 'B' valve and damper
Clutch 'Cl' damper
Clutch 'Cl' valve
Clutch 'C' valve and damper
Clutch
'D' valve and damper
Clutch 'E' damper
Clutch
'F' valve and damper
Reverse locking valve
Shift valve
1 - 2
Shift valve 2 - 3
Shift valve 3 - 4
Safety valve
Pressure valve
1
A Clutch 'A' D Clutch 'D B Clutch 'B' E Clutch 'E'
C Clutch 'C' F Clutch 'F'
C1 Clutch 'C"
19.
20.
21.
22.
23. 24.
25.
26.
27.
28.
29.
30.
31.
32.
33. 34.
35.
G
H J K
Pressure valve 2
Torque converter pressure valve
Lubrication valve
Lubrication valve
Lock
-up control valve
Modulation pressure valve
Main pressure valve
Gear change valve
Solenoid valves
MVllMV2l MV3
Pressure regulator
ECM
- inputs and outputs
Engine torque
Throttle valve Engine speed
(RPM) Transmission speed (RPM) Transmission rotary switch
Oil filter
Torque converter freewheel
(C) Clutch freewheel (D) Clutch freewheel (E) Clutch freewheel
Exhaust - Reduced pressure
=X= Th rott le - Modulation pressure
4= Orifice 2- Sump
- Main pressure - Lubrication pressure
- Converter pressure
Throttle pressure
Issue 1 August 1994 51
ZF Automatic Transmissions Service Manual
a
2.3.6 Fault Finding Chart (continued)
Problem
Starter motor does not operate
'osition 'R' - Reverse
3everse gear inoperative
Slipping and juddering
Harsh
engagement'p-R' chan
'N-R' change (below 1500RPF
engine speed)
Reverse lamp does not
illuminate (bulbs, fuses and
cables functioning correctly)
Possible Cause
Rotary switch adjustment.
Rotary switch wiring fault.
Rotary switch faulty.
Position
'P or 'N' not selected.
vIV2 faulty.
rNire to MV2 earthed.
3il filter dirty.
Damper
'6' faulty.
Clutch
'6' faulty (also no 3rd gear).
Clutch 'D' faulty.
Clutch
'E' faulty (also no engine braking
in 2nd and 3rd gears).
Pressure regulator valve 1 binding
Rotary switch wiring fault.
Rotary switch faulty.
Reverse gear inhibit valve activated.
Main pressure control valve seized (also
no forward drive in 'D' Drive).
'B'Clutch, 'D'Clutch or 'E' Clutch faulty.
Pressure regulator valve 1 binding
'F'Clutch drum sealing rings faulty
causing
loss of 'E' Clutch pressure.
Damper
'6' faulty (also no 2nd to 3rd
shift).
Pressure regulator valve 1 binding
Modulation pressure too high.
Rotary switch faulty.
Rotary switch setting incorrect.
Rotary switch faulty.
Rotary switch wiring fault.
Action
4djust switch.
qectify.
3ectify or renew.
Select 'F" or 'N'.
Renew valve block.
Renew harness.
Clean
/ replace filter and flush out
the
oil cooler and pipes.
Renew valve block.
Renew transmission.
Renew transmission.
Renew transmission.
Renew valve block.
Rectify.
Rectify or renew.
Renew valve block.
Renew valve block.
Renew transmission.
Renew valve block.
Renew transmission.
Renew valve block.
Renew valve block.
Check TCM Fault Codes.
Rectify or renew.
Adjust setting.
Renew.
Rectify.
Issue 1 August 1994 62