1994 FIAT PUNTO Speed

4D*4 Exhaust and emission control systems
d) DO NOT push- or tow-start the car - this will soak the catalytic converter
in
unbumed fuel, causing It to overheat when the engine does start. e) DO NOT switch off the ignition at high engine speeds. f) DO NOT use fuel or engine oil additives -these may contain substances harmful to the catalytic converter. g) DO NOT continue to use the car If
the
engine bums oil to the extent of leaving
a
visible trail of blue smoke.
h) Remember that the catalytic converter operates at very high temperatures. DO NOT, therefore, park the car in dry undergrowth, over long grass or piles of deed leaves after a long run. I) Remember that the catalytic converter is FRAGILE - do not strike it with tools during servicing work, j} In some cases a sulphurous smell
pike
that of rotten eggs) may be noticed from the exhaust. This Is common to many catalytic converter-equipped cars and
once the car has covered a few
thousand
miles tha problem should
disappear,
k)
The
catalytic converter, used on a
weW*
maintained and well-driven car, should las for between
SO
000 and
100
000
miles-If
the converter is no longer effective It
must
be renewed.
Diesel models Refer to the information given in parts i,
g, h
and I of the petrol models information given above.

5A«2 Starting and charging systems
Maintenance-free battery -charging Note: The following is intended as a guide only. Always refer to the manufacturer's recommendations (often printed on a label attached to the battery) before charging a battery. 13 This battery type takes considerably longer lo fully recharge than the standard type, the time taken being dependent on the extent of discharge, but it can take anything
up
to three days. 14 A constant voltage type charger is required, tooe set, when connected, to 13.9 to 14.9 votts wth a charger current below 25 amps. Using
mis
method, the battery should be usable within three hours, giving a voltage reading of 12.5 vofts. but this Is for a partially discharged battery and, as mentioned, full charging can
take
considerably longer. 15 If Ihe battery is to be charged from a fully discharged state {condition reading loss lhan 12.2 volts), have it recharged by your FIAT dealer or local automotive electrician, as Ihe charge rate is higher and constant super-vision during charging Is necessary.
3 Battery -removal and refitting
Note: Refer to Disconnecting the battery in ifte Reference Section of this manual before proceeding.
Removal 1 Slacken the clamp bolts and disconnect the ctamp from the battery negative (earth) terminal. 2 Remove the insulation cover (where fitted)
and
disconnect the positive terminal lead(s) in
Die same
way. 3 At the base of the battery, unscrew the bolt from the battery holding clamp plate and remove the clamp plate (see Illustration). A Remove the battery from Ihe engine compartment. 5 II necessary the mounting tray may be removed by unscrewing the bolts. On diesel models it will be necessary to remove the relay guard bolts as well.
Refitting 6 Refitting is a reversal of removal but make sure that the positive terminal is connected first followed by the negative terminal.
4 Alternator/charging system - >%•> testing in vehicle
Note: Refer to the warnings given in Safety first! and in Section 1 of this Chapter before starting work. 1 If the ignition warning light fails to Illuminate when the ignition is switched on, first check the alternator wiring connections for security. If satisfactory, check that the warning light bulb has not blown, and that the bulbholder is secure in its location in the instrument panel. If the light still fails to illuminate, check the continuity of the warning light feed wire from the alternator to the bulbholder. If all is satisfactory, the alternator is at fault and should be renewed or taken to an auto-electrician for testing and repair. 2 If the ignition warning light Illuminates when the engine Is running, stop the engine and check that the drivebelt is correctly tensioned (see Chapter 1A or 18) and that the alternator connections are secure. If all is so far satisfactory, have the alternator checked by an auto-electrician. 3 If the alternator output is suspect even though the warning light functions correctly, the regulated voltage may be checked as follows. 4 Connect a voltmeter across the battery terminals and start the engine. 5 Increase the engine speed until the voltmeter reading remains steady; the reading should be approximately 12 to 13 volts, and no more than 14 volts. 6 Switch on as many electrical accessories (eg. the headlights, heated rear window and heater blower) as possible, and check that the alternator maintains the regulated voltage at around 13 to 14 volts. 7 If ihe regulated voltage is not as stated, the fault may be due to worn brushes, weak brush springs, e faulty voltage regulator, a faulty diode, a severed phase winding or worn or damaged slip rings. The alternator should be renewed or taken to an auto-electrician for testing and repair.
3.3 Removing the battery clamp plate
5 Alternator -removal and refitting
Removal 1 Disconnect the battery negative terminal {refer to Disconnecting the battery In the Reference Section of this manual). 2 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). Remove tho right-hand front roadwheel. 3 Remove Ihe Inner cover from under the right-hand wheelarch for access to tho right-hand side of the engine. 4 Disconnect the cables from the rear Of the alternator (see illustration).
Petrol models 5 Loosen the pivot and adjustment bolts then swivel the alternator towards the engine and slip off the drivebelt. Note that the position of the rpm sensor will prevent complete removal of the drivebelt from the crankshaft puiley. 6 Unscrew and remove the pivot and adjustment bolts then unscrew the upper slot-mounted bolt. Withdraw the alternator from the engine (see illustrations).
Diesel models 7 For additional working room, unclip and remove the upper timing belt cover then unbolt and remove the lower timing belt cover.
5.4 Cable connections on the rear of the alternator
5.6a Alternator adjustment and pivot bolts (petrol engine) B Adjuster bolt C Pivot bolt 5.6b Removing the alternator (petrol engine)

5B*1
Chapters PartB:
Ignition system - petrol models
Contents
General information 1 Ignition system - testing 2 Ignriton HT coil - removal, testing and refitting 3 Ignition timing - checking and adjustment 4 Igrrtion system - check See Chapter 1A Spark plugs - renewal See Chapter 1A
Degrees of difficulty

Easy,
suitable for Falrty easy, sulabte Fafety difficult, suitable for competent Difficult, suitable for Very difficult, ^ novice with littie
1
for beginner with Fafety difficult, suitable for competent experienced DIY suitable for expert DIY or professional ^ expenence 1 some experience DIY mechanic mechanic *
suitable for expert DIY or professional ^
Specifications
General System type
firing order Ignition timing at Idle speed (non-adjustable, for reference onlyy. 6-valve engines: Single-point injection engine with manual transmission .... Single-point injection engine with automatic transmission.. Multi-point injection engine 16-valve engines
Ignition
coil winding resistance (at 20°C): Primary Secondary
Weber-Marelli static (distributorless), wasted spark Ignition system controlled by engine management ECU
1
-3-4-2 (No 1 cylinder at timing belt end of engine)
10® ± 3° BTDC 6° ± 3° STDC 13° ±3° BTDC 8° x 3° BTDC
0.495 to 0.605 ohms 6660 to 8140 Ohms

Ignition system - petrol models 5B®3
Chapter 1A tor further information. Also check tnat tha accelerator cable is correctly adjusted
as
described in the relevant part of Chapter 4. If the engine is running very roughly, check the compression pressures and the valve clearances as descnbed In the relevant parts of Chapters 1 and 2. 2
H
these checks fall to reveal the cause of the problem, the vehicle should be taken to a suitably equipped Fiat dealer for testing. A wiring block connector Is Incorporated in the engine management circuit Into which a special electronic diagnostic tester can be plugged. The tester will locate the fault quickly and simply alleviating the need to test all the system components Individually which is a time consuming operation that carries a high risk of damaging the ECU. 3 The only Ignition system checks which can
oe
earned out by the home mechanic are those cescribed in Chapter 1A, relating to the spark plugs, and the ignition coll test descnbed In this Chapter. If necessary, the system wiring and wiring connectors can oe checked as descnbed in Chapter 12, Section 2, ensuring that the ECU wiring connector(s) have first
been
disconnected.
3 Ignition HT coil - ^ removal, testing and refitting
Removal 1 On 6-valve engines, unscrew the boll and remove the plastic cover from the left-hand
end
of the cylinder head (see Illustration). On 15-valve engines, remove the air cleaner, resonator and Inlet air duct as described in Chapter 4B. 2 Identify the two HT leads for position then disconnect them from the coil HT terminals jsee illustration). 3 Disconnect the LT wiring plug.
4 Unscrew the mounting bolts and remove the relevant ignition coil from the end of the cylinder head,
Testing 5 Testing of the coil consists of using a multimeter set to its resistance function, to check the primary and secondary windings for continuity and resistance. Compare the results obtained to those given In the Specifications at the start of this Chapter. Note the resistance of the coil windings varies slightly according to the coil temperature; the results In the Specifications are approximate values for the coil at 20°C. 6 Check that there is no continuity between the HT lead terminals and the coil body/ mourning bracket. 7 Note that with the ignition switched on and the engine stationary, voltage will only be supplied to the ignition cotls for approx-imately 2 seconds. However, when tho engine is being cranked or running, voltage will be continually supplied. 8 If faulty, the coil should be renewed.
Refitting 9 Refitting ts a reversal of the removal procedure ensuring that the winng and HT leads are correctly reconnected (see illustration).
4 ignition timing • checking and adjustment
1 The Ignition timing is constantly being monitored and adjusted by the engine management ECU, and although it is possible to check the base ignition liming using a standard timing light It is not possible to adjust it. 2 For those wishing to check the ignition timing a stroboscope timing light will be required, and it will need to be the type which
3.1 Removing the ignition coll cover
can determine the amount of advance from the TDC markings on the crankshaft pulley or flywheel. It Is recommended that the timing mark is highlighted as follows. 3 Remove the plug from the top of the transmission then turn tho engine slowly (raise the front right-hand wheel and engage 4th gear) until the timing mark scribed on the edge of the flywheel appears in the aperture. Highlight the line with quick-drying white paint - typist's correction fluid is ideal. 4 Start the engine and run It to normal operating temperature, then stop it. 5 Connect the timing light to No 1 cylinder spark plug lead (No 1 cylinder Is at the timing belt end of the engine) as described in the timing light manufacturer's Instructions. 6 Start the engine, allowing it to idle at the specified speed (Chapter 1A), and point the timing light at the transmission housing aperture. Adjust the timing light until the TDC marks are aligned with each other and read off the amount of advance. 7 If the ignition timing is incorrect, the car should be taken to a Fiat dealer who will be able to check the system quickly using special diagnostic equipment. 8 After making the check stop the engine, disconnect the timing light and refit the plug to the transmission.
3.2 HT terminals (1) and LT wiring plugs (2) on the two ignition colls 3.9 Ignition colt connections

7A»1
Chapter 7 Part A:
Manual transmission
Contents
Gearchange lever and linkage - removal and refitting 2 General information 1 Manual transmission oil level check See Chapter 1A or 18 Manual transmission oil renewal See Chapter 1A or 1B
Manual transmission overhaul • general information 4 Manual transmission • removal and refitting 3 Reversing light switch • testing, removal and refitting 5
Degrees of difficulty

Easy, suitable
for Faiity
easy,
suitable FaMycffficult, ^ Difficult,
sutable fa-
Verycfifficutt, ^
novice with
little
1
for beginner with suitable
for
competent experienced DIY * * < siitable
for
expert
DIY
jR or professional ^ experience 1
some
experience DIYmechanic ^ mechanic * * < siitable
for
expert
DIY
jR or professional ^
Specifications
General Type
Designation: 1108 cc petrol engine 1242 cc petrol engine Non-turbo diesel engine Turbo diesel engine
Torque wrench settings Gear lever support nut Gear lever to mounting Reverse gear inhibitor cable to transmission Reversing light switch Selector rod-to-gear lever nut Speedometer drive Transmission-to-engine bolt/nut
Transverse mounted, front wheel drive layout with integral transaxle differential/final drive. 5 or 6 forward speeds, 1 reverse speed
C.S14.5.10 (5-speed) or C.514.6.10 (6-speed) C.514.5.1Q/13 (5-speed) C.514.5.13 (5-speed) C.510.5.17 (5-speed)
Nm Ibftl 6 4 49 36 30 22 40 30 17 13 12 9 es 63
1 Genera) Information
The transmission is contained In a cast-aluminium alloy casing bolted to the engine's left-hand end, and consists of the gearbox end final drive differential, Drive Is transmitted from the crankshaft via the clutch to the Input shaft, which has a spiined extension to accept the clutch friction
plate, and rotates in roller bearings at its right-hand end and ball bearings at its left-hand end (on 6-speed versions the left-hand extension rotates In a roller bearing). From the input shaft, drive is transmitted to tho output shaft, which rotates In roller bearings at Its right-hand end. and ball bearings at its left* hand end (on 6-speed versions the left-hand extension rotates in ball bearings). From the output shaft, the drive is transmitted to the differential crownwheel, which rotates with the differential case and gears in taper roller bearings, thus driving the sun gears and
driveshafts. The rotation of the differential gears on their shaft allows the inner roadwheel to rotate at a slower speed than the outer roadwheel when the car is cornering. The Input and output shaftB are arranged side by side, parallel to the crankshaft and driveshafts, so that their gear pinion teeth are In constant mesh. In the neutral position, the relevant input shaft and output shaft gear pinions rotate freely, so that drive cannot be transmitted to the output shaft and crownwheel.

Manual transmission 7A*3
3,8 Unscrew the nut and disconnect the gear selector rod from the lever on the transmission unscrew the locknut and adjusting nut from the end of the clutch cable and disconnect the cable from the transmission. Recover the damper block. On models with a hydraulically operated clutch, unscrew the mounting bolts, release the slave cylinder pushrod from the re&ase arm on the transmission, then position the cylinder to one side.
7 Unscrew and remove the reverse gear Inhibiting device from the transmission. Tie the cable to one side out of the way. 8 Unscrew the nut and disconnect the gear selector rod from the lever on the transmission (see illustration). 9 Pull out the clip then disconnect the gear engagement cable from the control lever and release the cable from the mounting bracket (see illustrations). 10 Unscrew and remove the two upper transmisslon-to-englne mounting bolts. Unscrew the single bolt securing the starter motor to the transmission. 11 Remove the air cleaner and air ducting with reference to Chapter 4A or 4B. This Is necessary In order to fit the engine hoist 12 On 5-speed transmissions, trace the wiring back from the electronic speedometer sensor and disconnect the connector located on the left-hand side of the engine (see illustration). 13 On 6-speed transmissions, unscrew the knurled nut and disconnect the speedometer cable from the top of the final drive housing. 14 Support the weight of the engine using a hoist attached to the engine lifting eyes, or alternatively use a trolley jack and block of wood beneath Ihe engine. 15 Unscrew the Lambda/oxygen sensor from the exhaust downpipe and position It In a safe place to prevent damage. 16 Unscrew the nuts securing the downpipe to the exhaust manifold, then lower It and support on an axle stand. Recover the gasket. 17 Unbolt the support bracket from the engine and transmission. Recover the spacer plate. 18 Unbolt and remove the transmission lower cover, 19 Unscrew the remaining starter motor mounting bolts and support tho starter motor to one side. 20 Loosen and remove the clips securing the left- and right-hand driveshaft gaiters to the transmission output shafts.
3.9a Remove the clip to release the gear engagement cable 21 Unscrew and remove the boils securing the left-hand swivel hub assembly to the front suspension strut, then separate the components and support the swivel hub on an axle stand. 22 Move the swivel hub assembly outwards and disconnect the inner end of the dnveshaft from the transmission output shaft. Support the shaft away from the transmission to prevent damage to the garters. 23 Working beneath the vehicle, unscrew the botts securing the rear engine mounting to the underbody then unscrew the bolts securing the mounting to the transmission and withdraw the mounting assembly from under the vehicle. 24 Unscrew the bolts securing the left-hand engine/transmission mounting to Ihe body then unscrew the bolts from the transmission and remove the mounting. 25 Support the woight of the transmission on a trolley jack then unscrew the remaining nut and bolt from the belihousing and pull the transmission away from the engine. Lower it and remove from under the vehicle. A Warning: Support the trans-mission to ensure that it remains steady on the jack head. Keep the transmission levet until the Input shaft Is fully withdrawn from the clutch friction plate. Refitting
26 Refitting is a reversal of the removal procedure, but note the following points. a) Apply a smear of high-melting-point grease to the clutch friction plate splines; take care to avoid contaminating the friction surfaces.
3.12 Electronic speedometer sensor fitted to 5-speed transmissions
3.9b Removing the gear engagement cable from the mounting bracket b) Tighten all bolts to Ihe specified torque. c) Fit new clips to secure the driveshaft gaiters to the transmission output shafts. d) Adjust the clutch cable (where applicable) as described In Chapter 6.
Diesel models
Removal 27 Seloct a solid, level surface to park the vehicle upon. Give yourself enough space to move around it easily. Apply the handbrake then jack up the front of tho vehicle and support on axlo stands (see Jacking and vehicle support). Remove both front wheels. 28 Unbolt the relay support then remove the batlery and mounting tray as described in Chapter 5A. 29 On models with a cable operated clutch, unscrew the locknut and adjusting nut from the end of the clutch cable and disconnect the cable from the transmission. Recover the damper block. On models with a hydraulically operated clutch, unscrew the mounting botts. release the slave cylinder pushrod from the release arm on the transmission, then position the cylinder to one side, 30 Unscrew the nut and disconnect the gear selector rod from the lever on the transmission. 31 Disconnect the gear engagement cable from the control lever then slide out the clip and release the cable from the mounting bracket. 32 Unbolt the electronic rev counter sensor from the upper rear of the belihousing and position it to one side (see illustration).
3.32 Electronic rev counter sensor located in the upper rear of the belihousing

7A«4 Manual transmission
33 Remove lha air cleaner front section and air ducting with reference to Chapter 4C. Also disconnect the injection pump vacuum pipe from the clips on the left-hand end of the cylinder head. This work is necessary in order to fit the engine hoist 34 Support the weight of the engine using a hoist attached to the engine lifting eyes, or alternatively use a trolley Jack and block of wood beneath the engine. 35 Unscrew the nuts securing the downpipe to the exhaust manifold, then lower it and support on an axle stand. Recover the gasket. 36 Unscrew the starter motor mounting bolts and support the starter motor to one side. 37 Disconnect the wiring from the reversing light switch on the front of the transmission. 38 Unscrew the nut and disconnect the earth cable from its stud. 39 Trace the wiring back from the electronic speedometer sensor and disconnect the connector located on the left-hand side ot the engine. If a mechanical speedometer Is fitted unscrew the knurled collar and disconnect the cabte from the transmission. 40 Unbolt and remove the transmission lower cover. 41 Using an Allen key unscrew the bolts securing the inner end of the left-hand driveshaft to the transmission flange. Remove the bolts and recover the spacer plates. Support the driveshaft on an axle stand. 42 Unscrew and remove the bolts securing the left-hand swivel hub assembly to the front suspension strut, then separate the components and support the swivel hub on an axle stand. 43 Move the swrvel hub assembly outwards and support the driveshaft away from Ihe transmission. 44 Using an Allen key unscrew the bolts securing the Inner end of the right-hand driveshaft to the intermediate shaft flange. Remove the bolts and recover the spacer plates. Support the driveshaft on an axle stand. 45 Remove the intermediate driveshaft with reference to Chapter 8. 46 Working beneath the vehicle, unscrew the bolts securing the rear engine mounting to the underbody then unscrew the bolts securing the mounting to the transmission and withdraw the mounting assembly from under the vehicle.
47 Unscrew the bolts securing the left-hand engine/transmission mounting to the body then unscrew Ihe bolts from the transmission and remove the mounting. 48 Support the weight of the transmission on a trolley jack then unscrew the remaining nut and bolts from the bellhousing and pull the transmission away from the engine.

A


Warning: Support the trans-mission to ensure that It remains steady o/i the jack head. Keep the transmission level until the Input shaft
1$
fully withdrawn from the clutch friction plate.
Refitting 48 Refitting is a reversal of the removal procedure, but note the following points. a) Appiy a smear* of high-meiting-point grease to the clutch friction piate splines; take care to avoid contaminating the friction surfaces. b) Tighten all bolts to the specified torque. c) Fit new clips to secure the driveshaft gaiters to the transmission output shafts. d) Adjust the clutch cable (where applicable) as described In Chapter 6.
4 Manual transmission overhaul -general Infomtatlon
Overhauling a manual transmission is a difficult and Involved Job for the DIY home mechanic. In addition to dismantling and reassembling many small parts, clearances must be precisely measured and, if necessary, changed by selecting shims and spacers. Internal transmission components are also often difficult to obtain, and in many Instances, extremely expensive. Because of this, If the transmission develops a fault or becomes noisy. Ihe best course of action is to have the unit overhauled by a specialist repairer, or to obtain an exchange reconditioned unit. Nevertheless, it is not impossible for the more experienced mechanic to overhaul the transmission, provided the special tools are available, and the Job is done in a deliberate step-by-step manner, so that nothing is overlooked.
The tools necessary for an overhaul include internal and external clrclip pliers, bearing pullers, a slide hammer, a sat of pin punches, a dial test Indicator, and possibly a hydraulic press. In addition, a large, sturdy workbench 8od a vice will be required. During dismantling o1 the transmission, make careful notes of how each component
1$
fitted, to make reassembly easier and more accurate. Before dismantling the transmission, it will help if you have some idea what area is malfunctioning. Certain problems can be closely related to specific areas In the transmission, which can make component examination and replacement easier. Refer to the Fault Finding Section at the end of this manual for more Information.
5 Reversing light switch -testing, removal and refitting ||
Testing 1 The reversing light circuit is controlled by a plunger-type switch screwed into the front of the transmission casing. If a fault develops, first ensure that Ihe circuit fuse has not blown. 2 To test the switch, disconnect the wiring connector, and use a multimeter (set to the resistance function) or a battery-and-bulb test circuit to check that there is continuity between the switch terminals only when reverse gear is selected. If this is not the case, and there are no obvious breaks or other damage to the wires, the switch is faulty, and must be renewed.
Removal 3 Access to the reversing light switch Is best achieved from under the vehicle. Apply the handbrake then jack up Ihe front of the vehicle and support on axle stands (see Jacking and vehicle support). 4 Disconnect the wiring connector, then unscrew It from the transmission casing.
Refitting 5 Refit the switch and tighten securely. 6 Reconnect the wiring then lower the vehicle to the ground.

7B«1
Chapter 7 Part B:
Automatic transmission
Contents
Accelerator pedal micro-switch(es) - checking and adjustment II Automatic transmission filter and fluid change See Chapter 1A Automatic transmission fluid level check See Weekly checks Automatic transmission • overhaul 12 Automatic transmission • removal and refining 2 Bectro-magnetic clutch - removal, inspection and refitting 3 BectrO'fnagnetic clutch brushes- removal, inspection and refitting . 4
Electronic control unit - removal and refitting 5 Gear selector cable - adjustment 6 Gear selector cable - removal and refitting 9 General information 1 Kickdown cable - adjustment 7 Kickdown cable - removal and refitting 6 Transmission oil pump - removal and refitting 10
Degrees of difficulty

Easy,
suitable for novice
with
ittle experience ^
Party
easy,
suitable for beginner
with
^r someexperienoe ^
Faiily
difficult,
^ suitable
for
competent
DIY mechanic
^

Difficult, suitable
for fe, experienced DIY >8J mechanic
Verydfficult, ^
suitable
for
expert DIY
or professional ^
Specifications
General Type Ratios (at transmission): Lowest Highest Final drive
Torque wrench settings Esnh cable Control unit Sectro-magnetic clutch to flywheel Transmission-to-engine bolt/nut ..
ECVT (Electronic Continuously Variable Transmission)
2.503 0.497 4.647:1
Nm Ibftt 14 10 5 4 34 25 85 63
1 Genera) information
I The automatic transmission fitted is designated ECVT (Electronic Continuously Variable Transmission). The main components
01
the transmission are an electro-magnetic dutch, a variable-ratio coupling, a final drive/ differential unit, and the associated control mechanisms (see illustrations overleaf) 2 The variable-ratio coupling consists of two pulleys and a flexible metal drivebelt. The effective diameter of the two pulleys can be varied to provide different transmission ratios between them. 3 During normal driving, the transmission automatically selects the ratio giving the best
compromise between economy and speed. When the driver depresses the accelerator pedal to the floor, a kickdown effect is provided, and the transmission selects a lower ratio for improved acceleration. 4 The gear selector control resembles that fitted to conventional automatic transmissions. The control positions are as follows: P (Parking) The transmission is mech-anically locked by the engage-ment of a pawl with a toothed segment on the driven pulley. R (Reverse) Reverse gean's engaged, N (Neutral) The transmission is In neutral. D (Drive) Normal driving position. Trans-mission ratio is varied automat-ically to suit prevailing speed and load.
L (Low) Prevents the transmission
moving into high ratios. Provides maximum acceleration end maximum engine braking. 5 The engine can only be started In positions P and N. A warning buzzer sounds If the selector is in any position other than P when the ignition is switched off or when the driver's door is opened. 6 The electro-magnetic clutch consists of a driving element boiled to the engine flywheel, and a driven element spiined to the transmission Input shaft. The degree of coupling between the (wo elements Is determined by the intensity of a magnetic field generated by a current passing through windings in the driven element. The magnetic field acts on a layer of metallic powder between the driving and driven elements. When no magnetic field is present, the powder is loose and the two elements are effectively