1994 JAGUAR XJ oil

ZF Automatic Transmissions Service Manual
1.1 ZF 4 HP 22 TRANSMISSION, GENERAL DESCRIPTION
The ZF Automatic Transmission covered in this section comprises a hydrodynamic torque converter, four speed gear
train and a hydraulic transmission control unit.
1. Torque converter
2. Throttle cable 3. 4-speed gear train 4. Output flange 5. Transmission control unit
Fig.
P \R
HP 22 ZF
6. Oil outlet (drain plug)
7. Selector cable attachment 8. Selector lever positions (see text) 9. Dipstick / oil filler tube 10. Oil cooler connection
.ansmission -
The transmission provides six gearshift positions:
0 Position 'P': Park - in this position the driven wheels are mechanically locked at the transmission.
0 Position 'R': Reverse - reverse gear selected.
0 Position 'N': Neutral - engine disconnected from driveline and wheels.
0 Position 'D': Drive - all four speed ranges are selected automatically with lock-up available in top gear only.
0 Position '3': automatic selection of the lowest three speed ranges only.
0 Position '2': automatic selection of the lowest two speed ranges only, transmission is prevented from shifting
up to the third and top speed ranges.
Immediate selection of a lower ratio is also available by 'kick-down' (pressing the accelerator down beyond the normal
full throttle position) for example when overtaking.
1.1.1 Torque Converter
The torque converter serves two main functions: it acts as a fluid coupling between engine and transmission geartrain
and it provides multiplication of engine torque when required.
The torque converter consists of an impeller, a turbine and a stator which is mounted on a one
-way clutch. The
converter cover is fixed to the impeller to seal the three elements within a common housing forming a closed circuit
through which oil flows when the transmission is in operation. The impeller is therefore connected to the engine and
rotates at engine speed when the engine is operating.
Torque multiplication is at its greatest when the vehicle is driven away from standstill. The stator bears against the
housing through its one
-way clutch and deflects the oil so that the flow is accelerated. As road speed builds up, the
impeller and turbine wheels turn at almost the same speed, so that the stator ceases to accelerate the oil flow and in- stead is disengaged from the housing and turns freely in the flow of oil. At this stage, the torque converter acts as a
fluid coupling.
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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
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ZF Automatic Transmissions Service Manual
Valve
Reverse Gear
Clutches 'B','D' and 'E' are
engaged.
As the front planet gear carrier of epicyclic gear set
'1' is
locked, the direction of output shaft rotation is reversed.
Epicyclic gear set
'2' also rotates as a solid block.
Summary of function
J4L-698
Fig. 1
Pressure regulating
1-2 shift valve
2
-3 shift valve
1.1.4
This housing contains the output shaft and speed governor and the parking lock mechanism. The governor comprises
two spring loaded valves, a spindle and a weight; the governor is influenced by centrifugal and hydraulic forces and
supplies a varying hydraulic pressure.
The parking lock pawl operates on
a toothed wheel attached to the output shaft speed governor; the mechanism is
operated from the selector (position 'I") by actuator rod.
Transmission Output Shaft Extension Housing
Varies line pressure as required
Line pressure to
C & C1 clutch valves and dampers
Line pressure to
C1 clutch (2nd); line pressure to B clutch (3rd)
1.1.5 Transmission Control Unit
The hydraulic control unit comprising a series of valve blocks housing the manual (selector) valve, control pistons and
pressure valves, is attached to the underside of the transmission housing; the unit controls the operation of the gear
train clutches and directs oil pressure to the appropriate system components (refer to illustrations, pages 5 to 7 ) to
operate the transmission. The valve blocks are connected to a main gallery plate.
Line pressure from the hydraulic pump is supplied initially to the pressure regulating valve, manual valve, governor,
3
-4 shift valve, 'E' clutch and damper, throttle valve, modulator valve and torque converter pressure (and reversing)
valve. The function of each of the valves in the control unit and the governor valve is summarised in the table below.
2nd gear inhibit
3
-4 shift valve
Throttle valve
Modulator
Converter
& Reversing
Reverse inhibit
F Clutch inhibit
Converter clutch hysteresis
Converter clutch lock
-up
Converter clutch damper
Clutch valves
& Dampers
Governor Line pressure
to 2
-3 shift valve
Line pressure to
E clutch (3rd); line pressure to F clutch (4th)
Throttle pressure to modulator and shift valves
Modulated throttle pressure fed to clutch dampers and valves
Line pressure to lock
-up clutch; lubrication oil to cooler
Line pressure to B
& D clutches
Governor pressure to 3
-4 shift valve inhibited in reverse
Governor pressure to converter clutch hysteresis valve
Line pressure to converter pressure valve
(D4 selected)
Aids quality of converter clutch application
Aids quality of clutch application relevant to modulator
& line pressures
Varies pressure in accordance with road speed
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1.1.6 Gearshift Selection
Gearshift selection is by movement of the shift lever which through a selector cable causes repositioning ofthe manual
(selector) valve to direct oil pressure to the required shift valve. The automatic shift points are determined by acceler- ator position and road speed: throttle movement moves a cam on the throttle valve, directing oil pressure to the shift
valves and modulator valve, road speed modulates hydraulic pressure through a centrifugal governor driven by the
transmission output shaft. Operation
of the hydraulic control system is shown diagrammatically in the circuit dia
-
grams on the following pages.
I I
I
I
2 -3- I
I I
I
I
- I
I I 1 4 -5 - - -
+ ! + I I 'I 10 I I
I
I 1
1, 1-Y I
I I
I
I
1. Engine 8. Pump regulator valve 2. Torque converter 9. Damper
3. Pump 10. Governor valve 4. Clutch & gears 11. Shift valve 5. Governor 12. Kickdown cable &throttle cam 6. Shift 13. Throttle / modulator valves 7. Solenoid valve 14. Transmission housing
Fig.
1 Schematic Diagram of Hydraulic Control
I. 1.7 Throttle Valve Mechanism (kick-down)
The throttlevalve or 'kick-down' mechanism comprises a cable connected between throttle body pedal and the throttle
valve cam/ quadrant located on the selector valve shaft; the cam operates the throttle valve housed within the throttle
valve block. The travel of the valve is proportional to throttle positions and alters shift speeds and pressures during
gearshifts to take account of throttle position. The mechanism also provides for immediate selection of a lower
ratio (eg when overtaking) by depressing the accelerator beyond the normal full
-throttle position. 'Kick-down' is oper- ated by movement of the throttle cable into the 'kick-down' position causing full movement of the throttle valve and
directing oil flow to the shift valves.
1.1.8 Starter Inhibit Switch
The starter inhibit switch prevents the starter motor from being operated when the shift lever is not in position 'P' - Park or position 'N'- Neutral. The switch is located in the gear selector housing.
I. I. 9 Gearshift Interlock
A brake pedal /shift lever interlock is incorporated in the gearselector mechanism. Theshift lever may only be moved
from the 'P'- Park position if the ignition key switch is in position '11', and the foot brake pedal is applied. The ignition
key cannot be removed from the ignition switch unless the shift lever is in the 'P' -Park position. Once the ignition key
has been removed, the shift lever is locked in the park position.
The gearshift interlock is operated by an electrical solenoid located adjacent to the selector; an override latch is incorpo
- rated into the mechanism to enable the gearshift interlock to be manually overridden in the event of electrical failure
or when towing.
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ZF Automatic Transmissions Service Manual
1.2 HYDRAULIC CIRCUIT DIAGRAMS
Key To Hydraulic Circuit Diagrams (commencing on page IO)
1. Governor 16. 1 - 2
Shift Valve
2. Torque Converter 17.
Clutch
'C' Valve
3. Sump
18. Clutch 'C" Damper
4. Pump 19.
Clutch
'C" Valve
5. Pressure Regulating Valve 20.
2
- 3 Shift Valve
6. Clutch
'B' Valve And Damper 21.
2nd Gear Inhibit
7. Clutch 'D' Valve And Damper 22.
Throttle Valve
8. Reverse Gear Inhibit 23. Converter Clutch Lock-up Control Valve
9. Manual Valve 24.
Converter Clutch Hysteresis Valve
IO. Oil Cooler 25. 3 - 4 Shift
Valve
11. Converter And Reversing Valve 26.
Clutch 'F' Valve And Damper
12. Converter Clutch Damper 27.
Clutch
'A' Damper
13. One
-way Valve
14. Modulator Valve
15. 1st Gear Inhibit
A Clutch'A'
B Clutch'B'
C Clutch'C'
C1 Clutch 'C"
D Clutch'D'
E Clutch'E'
F Clutch'F'
Exhaust
Throttle
Orifice Branch
Main Pressure
Converter Pressure
Throttle Pressure
28. Clutch 'E' Damper
29. Clutch 'F' Inhibit Valve (Reverse)
Vlll HII Governor Pressure
IX - Locking Pressure
X -1- Modulation Pressure
XI - Pump Pressure
XI1 Lubrication Pressure
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ZF Automatic Transmissions Service Manual
1.3 FAULT DIAGNOSIS
The followina tables are intended as a auide to diaanosis of Dossible faults in the ZF 4 HP 22 transmission. When the
fault involvesa leak, it is recommendedthat it is located by the use of a crack detection fluid, eg Met-L-Check, which
is available in spray form and permits the leak to be located after a short test drive.
1.3.1 Initial Checks
Note: Before attempting diagnosis, ensure that the following settings are checked:
Transmission oil level.
. Ensure that the transmission is at normal operating temperature, eg by conducting a road test. If starting from cold,
. Check that the vehicle is on level ground.
. Firmly apply the parking and footbrakes and run the engine at idle speed.
. To ensure that the system is primed, slowly move the selector lever through all the gear positions.
. With the engine still running, engage ‘P‘ Park, withdraw the dipstick and wipe with a lint free cloth.
. Replace the dipstick slowly and withdraw it noting the level.
. Top up as required and recheck the level.
check
for presence of oil on dipstick at idle
in Park before start of road test.
1.3.2 Engine Tune
Selector cable adjustment.
Check gear selection in all selector positions.
If in doubt, select ’N’, disconnect the cable at the gearbox selector lever, check that the gearbox lever is in ’N’ position
. Adjust as necessary, see Vehicle Service Manual.
(third
detent from the rear) and refit the selector cable ball pin to the lever.
Kickdown switch adjustment, see Vehicle Service Manual.
1.3.3 Stall Test
. Ensure the transmission is at normal running temperature.
. Fully apply the parking brake.
. Fully depress the footbrake.
= Select position ‘D‘- Drive.
. Fully depress the accelerator(’kick-down’ detent fully depressed).
. Note the tachometer reading.
Start
the engine.
. Compare the tachometer reading to the specification.
CAUTION: This test must not last more than 5 seconds. Always allow the engine to idle for at least 2 minutes be- tween tests to allow the transmission fluid to cool down. Do not carry out more than three tests in any
half-hour.
1.3.4 Road Test
Fully check all shift speeds and note. Compare the results with the specification in addition to general observations
of transmission behaviour, noises, leaks etc., and consult the following Fault Finding Chart.
CAUTION: When renewing the transmission, ALWAYS flush out the oil cooler and feed and return pipes.
1.3.5 Electrical Checks
If any electrical component fault issuspected, referto the Electrical Diagnostic Manual (EDM) to verify the failure mode
before a repair or replacement is attempted.
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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.
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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
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