automatic transmission FIAT PUNTO 1994 176 / 1.G Owner's Manual

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

7B*2 Automatic transmission
disconnected. As the magnetic field increases, the powder sticks together, and the coupling between Ihe elements becomes Increasingly rigid. 7 Selection of reverse, neutral and forward gears is by the movement of a sliding sleeve on a hub keyed to the drive pulley shaft. In forward gear, the sleeve engages with the gear on the end of the input shaft, which is then locked to the drive pulley shaft. When reverse is selected, the sleeve engages with reverse driven gear, which is in constant mesh with an idler gear driven by transfer gears from the input shaft gear. In neutral, the sleeve Is in an intermediate position, and the
two shafts are not connected. 8 Tho drive pulley and driven pulley both consist of fixed and moving halves. The movement of ihe drive pulley halves is controlled hydraulically, while the driven pulley halves move under the influence of a spring and the tension exerted by the drivebeit. As the drive pulley opens, the driven pulley closes, and vice-versa. In this way, the transmission ratio between the two pulleys can be varied. The ratios are continuously variable between preset limits; the difference between the lowest and highest ratios available is approximately 5:1. 9 Hydraulic pressure is generated by a gear-
type pump Inside the transmission. The punp driveshaft runs inside the Input and drive pulley shafts, and Is splined to the centred the engine flywheel. This means that hydreulc pressure is only generated when the engine is running, which is why a car with this type ot transmission cannot be push- or tow-started 10 Application of hydrautic pressure to the pulley halves is via a control unit, which receives information on accelerator pedal position, transmission selector lever position, transmission ratio currently in use, and drive pulley speed. From this information, the control unit determines whether, and in which direction, lo change the pulley ratios.
1.1 a Cutaway view of the ECVT (electronic continuously variable transmission) 7 Electromagnetic dutch 3 Drive pulley 5 Metal drivebeit 7 Hydraulic controt unit 2 Gear selector sleeve A Dnven pulley 6 Final drive reduction gears

Automatic transmission 7B*3
11 When reverse gear Is selected, the control unit keeps the transmission In tow ratio, if this were not the case, it would, In theory, be possible to drive as fast In reverse as in forward gear. 12 An electronic control unit supplies the current to energise the clutch. The control unit receives signals concerning engine speed, road speed, accelerator pedal position, and gear selector position, Sensors include the following. a) Engine rpm sensor (from the Injection/ignition control unit) b) Accelerator pedal switch
c) Throttle valve position sensor d) Selector lever position sensor e) Vehicle speed sensor f) Coolant temperature sensor g) Air conditioning sensor h) Brake switch I) Torque signal
13 The final drive/differential unit Is conventional. Drive from the driven pulley is transmitted to the differential by an Intermediate reduction gear. 14 The ECVT incorporates a warning light which illuminates when a fault occurs.
Precautions 1$ Observe the following precautions to avoid damage to the automatic transmission: a) Do not attempt to start the engine by pushing or towing the car. b) If the car has to be towed for recovery, the distance must not exceed 12 miles (20
km),
and the speed must not exceed
19
mph
(30 kph).
If these conditions cannot be met, or If transmission damage is suspected, only tow the car with the front wheels clear of the ground. c) Only engage P or R when the vehicle is stationary.
1.1b Electromagnetic f Coil 2 Signal from vehicle speed sensor 3 Transmission 4 Electromagnetic powder 5 Drive shaft (driven by crankshaft) $ Transmission input shaft 7 Electromagnetic clutch housing 8 ECVT control unit
clutch control system 9 Accelerator pedal micro switch 10 Throttle
vafve
opening position potentiometer 11 Multifunction switch 12 Ignition switch
13
Air conditioning
signal
14 Engine PPM
signal
15 Accelerator pedal 16 Coolant temperature signal 17 Injection/ignition control unit 18 8attery
1.1c Hydraulic control system 3 Injection/ignition control unit 4 Air conditioner sensor
signal
6 Coolant temperature signal 7 Clutch signal 8 Engine RPM
signal
9 ECVT warning light 10 Selector lever position 11 Accelerator
pedal
switch/throttle
valve
potentiometer/torque signal 12 Brake switch 13
ECVT
control unit 14 Signal from vehicle speed sensor
15
Accelerator pedal position switch
16 Pulley ratio 17 Input shaft RPM 18 Primary oil pressure
19
Primary pulley 20 Electromagnetic clutch 21 Pressure regulating solenoid valve 22 Oil pressure control valve 23 Secondary oil pressure 24 Slip ring 25 Drive from engine 26 Oil pump 27 Vehicle speed sensor 28 Secondary pulley 29 Belt and pulley 30 Drive to drlveshafts

7B*4 Automatic transmission
2 Automatic transmission - ^ removal and refitting St
Removal 1 Select 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 the vehicle and support on axle stands (see Jacking and vehicle support). Remove both front wheels, 2 Remove the battery and mounting tray as described In Chapter 5A. 3 Remove the air cleaner and air inlet duct as described In Chapter 4A. 4 Disconnect the kickdown cable at the sector on the throttle housing and detach It from the mounting on the camshaft cover. Also release the cable from the support on the left-hand end of the cylinder head. 5 Disconnect the wiring connectors on the transmission. 6 Disconnect the fluid inlet and outlet Unas from the heat exchanger on top of the transmission. 7 Pull the fluid level dipstick from Its tube on the front of the transmission and tape over the top of the tube to prevent dirt entry. 8 Unscrew and remove the retaining pin and disconnect the speed selector cable from the top of the transmission. 9 Unscrew the upper bolt securing the starter motor to the transmission. 10 Unscrew the upper bolts securing the transmission to the engine. 11 Support the weight of the engine using a hoist attached to the engine lifting eyes, or alternatively UBO a trolley jack and block of wood beneath the engine, 12 Remove the screws and remove the front wheel arch liner from under the left-hand wheel arch. 13 Unscrew the nut securing the earth cablo to the transmission. 14 Using a punch drive out the roll pins securing both driveshafts to the final drive output shafts. 15 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. 16 Move the swivel hub assembly outwards and slide the inner end of the driveshaft from the splines on the transmission output shaft. Support the shaft away from the transmission to prevent damage to the gaiters. 17 Unscrew the lambdafoxygen sensor from the exhaust downpipe and position it In a safe place to prevent damage. 18 Unscrew ihe nuts securing the downpipe to Ihe exhaust manifold, then lower It and suppon on an axle stand. Recover the gasket. 19 Unscrew the knurled nut and disconnect the speedometer cable from the top of the final drive housing.
3-2 Locking the flywheel when removing the electromagnetic clutch 20 Unscrew the remaining bolt securing the staner motor to the transmission 21 Unbolt and remove Ihe lower flywheel cover from the transmission. 22 Working beneath the vehicle, unscrew the bolts securing the rear engine mounting to the underbody then unscrew the bolts securing the mounting lo the transmission and withdraw the mounting assembly from under the vehicle. 23 Unscrew the bolts securing the left-hand engine/transmission mounting to the body thon unscrew the bolts from the transmission and remove the mounting. 24 Support the weight of the transmission on a trolley jack then unscrew the remaining nut and bolt from the bellhouslng and pull the transmission away from the engine. Lower it and remove from under the vehicle.

A


Warning: Support the transmission to ensure that It remains steady on the Jack head. Keep the transmission level until the Input shaft and pump shaft are fully withdrawn from the electromagnetic clutch housing.
Refitting 25 Refitting is a reversal of the removal procedure, but note the following points. a} Apply a smear of high-melting-point grease to the splines of the transmission input shaft and oil pump driveshaft.
3.6 Checking the resistance of the clutch windings 1 Slip rings
0) Tighten all nuts and bolts to the
specified
torque, where given, c) Renew both driveshaft roll pins.
3 Electro-magnetic clutch • & removal, inspection 5. and refitting ^
Removal 1 Remove Ihe transmission as described n Section 2. 2 Turn the flywheel so that two of the lour mounting bolts are accessible, Hold tha flywheel stationary then unscrew Ihe tvrt bolts. To hold the flywheel, Insert a wida bladed screwdriver In the ring gear teeth or alternatively use a piece of angle iron against one of the retaining bolts temporarily Inserted in the cylinder block (see illustration). 3 Turn the crankshaft half a turn and unscrew the remaining bolts, then withdraw the electromagnetic clutch.
Inspection 4 Turn the driven element by means of tha slip rings, and check that the bearing is not noisy or rough. 5 Inspect the slip rings for burning or other damage. Clean them if necessary using fid and a clean rag. 6 Check the resistance of the clutch windings, using an ohmmetor connected across the slip rings (see Illustration). The resistance at 20*0 should be 2 to 4 ohms. 7 Check the Insulation of the windings, using an ohmmeter connected between either sip ring and the body of the clutch (see illustration). Resistance should be Infinity. 8 If the clutch fails any of the foregoing checks, renew it. Apart from the brush gear, Individual spares are not available.
Refitting 9 Refitting is a reversal of removal but tighten all bolts to the specified torque.
windings

Automatic transmission 7B«5
4 Electro-magnetic dutch brushes - removal, inspection and refitting
Removal 1 Remove the battery and battery tray as described in Chapter 5A. 2 Disconnect the wiring connector for the brushes. The brush holder is located near the dlp9tick tube. 3 Unscrew the mounting screws and with-draw the brush holder from the transmission (see illustration).
inspection 4 Inspect the brushes. If they ere worn down to the limit lines, or if they do not move smoothly in their holders, renew the brush carrier assembly (see illustration}. Note: Be careful not to damage the brush supply leads whan checking the brushes for free movement II is not possible to renew the brushes separately,
Refitting 5 Refitting is a reversal of removal.
5 Electronic control unit • removal and refitting
Removal 1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual).
4.3 Brush holder mounting screws on top of tho transmission
2 Unscrew the mounting screws and remove the centre console. 3 Unscrew the mounting bracket screws, lower the control unit then disconnect the two wiring connectors (see Illustration). Withdraw the unit from inside the vehicle.
Refitting 4 Refitting Is a reversal of removal.
6 Kickdown cable -removal
and
refitting I
This operation involves the removal of the hydraulic control unit from inside the trans-mission. It should therefore be left to a Flat dealer or other specialist.
1 Remove the air cleaner and air Inlet duct assembly as described in Chapter 4A. The throttle cable is located on top of the throttle housing sector and the kickdown cable is located on the bottom of the sector (see Illustration). 2 Turn the throttle housing sector fully clockwise so that the throttle Is wide open, then position the kickdown outer cable so thai its Inner cable is slightly tensioned. Make the adjustment at the two adjustment nuts on the support bracket. 3 Check and if necessary adjust the accelerator cable as described In Chapter 4A. 4 Fully depress the accelerator pedal then check that there is approximately 0.5 to 1.0 mm free travel available on the kickdown cable. If necessary re-adjust the kickdown cable until It is set correctly. 5 Road test the vehicle and check for correct operation.
6.3 Wiring connectors on tho electronic control unit 7.1 The throttle cable (A} Is located on top of the throttle housing sector and the kickdown cable (8) on the bottom

7B*6 Automatic transmission
Gear selector cable -adjustment
1 Remove the battery and tray as described In Chapter 5A for access to the transmission. 2 Disconnect the selector cable from the lever on Ihe transmission. 3 Move the selector fever inside the vehicle to the N (Neutral) position, then move the lever on the transmission to Its central (Neutral) position. Locate the cable end over the lever. If the cable end fitting does not line up exactly with the hole In Ihe lever, loosen the adjustment nut and reposition the end fitting. 4 With the adjustment correct reconnect tha cable to the lever, then move the selector lever to the P (Park) position. Check that the lever on the transmission has also moved to the P position. 6 Refit the battery and tray as described in Chapter 5A. 6 Road test the vehicle, and check for correct operation in all selector lever positions.
9 Gear selector cable -removal and refitting at
7 Inside the vehicle disconnect the selector cable from the bottom of the selector lever (hen remove it from the support bracket, a Withdraw the cable into the engine compartment, and remove it.
Refitting 9 Refitting is a reversal of removal, but adjust the cable as described in Section 8. 10 Check that It is only possible to start the engine in positions P and N. Reposition the selector lever switch If necessary. 11 Road test the vehicle, and check for correct operation In ell selector lever positions.
10 Transmission oil pump - & mnvtiifll rAtiMlitA removal a/id refitting
Removal 1 Using an Allen key. unscrew the screw and remove the selector lever knob from the lever. 2 Remove the oddment tray and the ashtray. 3 Remove the screws and withdraw the centre console and selector mechanism cover. 4 Unscrew the mounting screws, slightly lift the centre console, then disconnect the wiring and remove the console, 5 Remove the battery and tray as described in Chapter 5A for access to the transmission, 6 Disconnect the selector cable from the lever on the transmission.
Removal 1 Apply the handbrake, then lack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove the left-hand wheel. 2 Unscrew the screws and remove the wheel arch liner. 3 Working through the left-hand wheel arch, remove Ihe three bolts which secure the oil pump. 4 Attach a slide hammer to the oil pump, using the two tapped holes provided. Withdraw the pump using the slide hammer. Be prepared for some oil spillage. Recover the gasket end O-ring (see illustrations). 5 If the pump is defective, it must be renewed; no spares are available.
Refitting 6 Before refitting Ihe oil pump, clean Ihe mating surfaces of the transmission and pump. 7 Rt the oil pump, U9ing a new gasket and a new O-ring. Secure the pump with the three bolts.
8 Refit the wheel arch liner, then refit tto wheel and lower the vehicle to the ground. 9 Check the transmission fluid level » described earlier in this Section, and top-upif necessary.
11 Accelerator pedal & mfcro-Bwftcb(es) -checking
and
adjustment ^
1 Correct adjustment of the micro-awtlch which senses the accelerator pedal position s essential for correct operation of the clutch.
A
quick check can be made by listening for the switch clicking as the accelerator a depressed. For an accurate check, proceed as follows. 2 Disconnect Ihe mlcroswitch wiring connector (nside the vehicle. Connect a continuity tester across the terminals of the switch, located at the top of (he pedal box (see Illustration}. 3 Remove the air cleaner and air ducting as described in Chapter 4A. 4 With the accelerator pedal releassd, th« switch must be closed (zero resistance). Slowty depress the pedal, and check that the switch opens when the throttle valve on the throttle housing is 30° open. This will occur when the pedal has travelled between 3 and 7 mm. Adjust the switch position if necessary. 5 If the switch is permanently open or permanently closed, and adjustment makes no difference, renew ft. 6 Remake the original wiring connections on completion,
12 Automatic transmission -overhaul
Apart from the operations described earlier in this Section, transmission overhaul should be entrusted to a Rat dealer or transmission specialist.
10.4a Using a slide hammer to remove the oil pump from the transmission 10.4b Automatic transmission oil pump O-dng (1), housing (2) and gasket (3) 11.2 Continuity tester connected ecross the accelerator pedal micro-switch