GENERAL REMARKS - GEARBOX

1.9 JTD 8V, 1.9 JTD 16V

SPECIFICATIONS

The M32 manual gearbox is designed to be installed in front wheel drive systems with the engine tranversely mounted. The code M32 means that the gearbox has been designed to support a transmission with a maximum torque of 320 Nm.

1. Gearbox casing

2. Clutch casing

3. Differential casing

4. Differential internal casing

5. Differential ring gear

6. Main shaft (A)

7. Clutch control coaxial actuator

8. Layshaft (B)

9. Second layshaft (C)

The specific features are:

- manual gearbox with fixed idler with six transmission ratios plus reverse;

- all gears with synchromesh (including reverse);

- toothed wheels with helical teeth;

- three shafts, one input plus two secondary (upper and lower);

- differential integrated in the gearbox casing;

- dry weight 46.7 km;

- activation by hydraulic clutch;

- designed for matching with twin mass flywheel;

- body divided into three sections to facilitate maintenance operations.

COMPOSITION OF THE GEARBOX

Inside the gearbox each transmission ratio is produced by means of a pair of gears that mesh constantly with one freewheeling on the respective shaft. Reverse gear is an exception and is produced by means of a train with three gears to reverse the direction of power.

The main shaft receives the drive directly from the crankshaft; when a gear is selected, the torque is transferred, via the pair of gears for the speed selected, to the layshaft and, from there, to the fixed idler, connected to the differential.

Engagement diagram

First and second speed

FIRST SPEED ENGAGEMENT

SECOND SPEED ENGAGEMENT

In first speed the power enters the gearbox via the main shaft and is transmitted, through the fixed drive gear, to the driven gear for the first speed fitted in neutral on the lower layshaft. The activation of the synchronizer (for first and second speed) makes the toothed wheel form one piece with the layshaft and, by means of the fixed idler wheel, with the differential.

By moving the synchronizer in the opposite direction, the driven gear for the second speed forms one piece with the layshaft; the second speed is produced in this way.

Third and fourth speed

THIRD SPEED ENGAGEMENT

FIFTH SPEED ENGAGEMENT

The power enters the gearbox via the main shaft and, by means of the fixed drive gear, is transferred to the driven gear, fitted on the upper layshaft; the activation of the synchronizer (for third and fourth speed) makes it possible to transfer the power to the toothed wheel for the fixed idler, also forming one piece with the differential ring gear, like the one on the lower shaft.

Moving the synchronizer in the opposite direction produces the engagement of fourth speed.

Fifth and sixth speed

FIFTH SPEED ENGAGEMENT

SIXTH SPEED ENGAGEMENT

The power enters the gearbox via the main shaft and, by means of the fixed drive gear, is transferred to the driven gear, fitted on the lower layshaft; the activation of the synchronizer (for fifth and sixth speed) makes it possible to transfer the power to the toothed wheel for the fixed idler, also forming one piece with the differential ring gear.

To engage sixth speed, the same synchronizer is activated in the opposite direction to previously.

Reverse gear

REVERSE GEAR ENGAGEMENT

The power entering the gearbox is transferred from the main shaft to the gear for first speed fitted on the lower layshaft; this gear acts as a free wheel because it transfers the power to the toothed wheel for reverse gear fitted on the upper layshaft with which it meshes; at the same time, this allows the reversal of the power. The synchronizer for reverse gear makes the wheel form one piece with the upper layshaft, transferring the power to the differential.

Toothed wheels

MATERIALS AND MACHINING: the toothed wheels are subjected to variable loads over a period of time which produce stresses and fatigue; for these reasons nickel chrome steel alloys are used which afford good mechanical resistance; after machining the toothed wheels firstly undergo a finishing process (grinding) and afterwards a heat treatment that improves their resistance properties to fatigue and wear (binding and tempering).

SPECIFICATIONS: the toothed wheels used have helical teeth. The adoption of toothed wheels with helical teeth allows the transmission of higher torques compared with those of the same size with straight teeth; in addition, toothed wheels with helical teeth afford smoother and quieter operation; another important feature of the gears in the gearbox in question is the teeth with a high covering factor; several teeth (and not just one) are always meshed, with the advantage of smooth transmission.

Shafts

Main shaft (a)

1. Front bearing

2. Rear bearing

3. 1st speed gear

4. 2nd speed gear

5. 3rd-5th speed gear

6. Spacer

7. 4th speed gear

8. 6th speed gear

9. Needle bearings

SPECIFICATIONS: the gearbox input shaft has all the toothed wheels forming one piece: in particular the toothed wheels for first and second are directly on the part, i.e. they physically form part of the shaft as they are produced through mechanical machining processes, whilst the others for third and fifth speeds and fourth and sixth are fitted by means of splining in the actual shaft and are an interference with on the shaft itself.

The gearbox main shaft is supported by two conical roller bearings.

Layshaft (b)

1. Pinion

2. Front bearing

3. Rear bearing

4. Reverse gear

5. Reverse single cone synchronizer

6. Spacer

7. 3rd speed gear

8. 3rd-4th speed double cone synchronizer

9. 4th speed gear

SPECIFICATIONS: the upper layshaft supports the wheels that produce third and fourth forward speeds and reverse; these wheels are all fitted in neutral on roller bearings.

There are two synchronizers: one, triple cone synchronizer, designated to form one piece between the wheels for third or fourth speed with the shaft, the other single cone synchronizer, for reverse.

There is a toothed wheel on the shaft that transfers the power to the differential ring gear.

The shaft is supported by two conical roller bearings.

Second layshaft (c)

1. Pinion

2. Front bearing

3. Rear bearing

4. 1st speed gear

5. 1st-2nd speed triple cone synchronizer

6. 2nd speed gear

7. 5th speed gear

8. 5th-6th speed single cone synchronizer

9. 6th speed gear

The wheels that produce first, second, fifth and sixth forward speeds are fitted on this shaft; the toothed wheel for first speed is also involved in producing reverse.

The shaft is supported by two conical roller bearings.

Synchronizers

The diagram shows the exploded view of the synchronizer for third and fourth speeds. It is the triple cone type to ensure optimum continuity and smooth transfer of torque between the shafts.

1. On the synchronizer for third and fourth speeds, two of the three cones contain a carbon friction ring

2. The synchronizer for first and second speeds also has this friction ring on all three cones.

3. The synchronizers for fifth and sixth speeds and reverse are the single cone type (they do not have the first two cones).

In the case of the synchronizer for fifth and sixth speeds and reverse, given the lesser torque produced by the actual gearbox, a single cone synchronizer is used.

Gear selector and engagement assembly

The gear selector and engagement assembly comprises a kinematic arrangement connected, by means of cables, to the control lever in the passenger compartment.

The kinematic arrangement has two possible movements: vertical travel designed to select the synchronizer; movement in a rotary direction is designed to activate the fork for the synchronizer.

1. Gear engagement lever

2. Gear selection lever

1.9 JTS, 2.2 JTS

SPECIFICATIONS

A new generation Getrag gearbox has been fitted on the 2.2 16v version.

The main features of the gearbox are:

- reduced axial size

- excellent manoeuvrability in all gears

- extremely quiet operation.

The gearbox configuration is tranverse with three shafts and an internal differential. There are HRC teeth for all the gears super finished after a thermal treatment.

The gearbox and clutch casings have been designed to produce the same resistance at minimum weight (FEM/FINITE ELEMENT METHOD).

The gears all have synchromesh including reverse and the synchronizer rings are all made from brass with a Borg Warner type molybdenum coating.

The first and second speed gears, including the synchronizer rings, are fitted on an idler shaft between the main shaft and the layshaft.

The gears and synchronizers for third and fourth speeds are located on the main shaft and for fifth and reverse on the layshaft.

For first and second speeds, the gears used the most, the synchronizer rings are the double cone type and ensure reduced engagement forces compared with traditional or single ring type synchronizers.

The internal gear control system is produced by means of three selection planes with a central gear positioner with a bearing.

The clutch is hydraulically operated with the C.S.C. system co-axial on the main shaft inside the gearbox.

The components inside the gearbox are lubricated dynamically, by means of the oil flowing through the ducts in the casings and the ports in the shafts as well as additional plastic ducts; all of this allows improved torque transmission and better protection against wear. This system has a device for the recovery of the clutch plate wear which allows the load on the clutch pedal to remain constant throughout the life of the vehicle

The advantages of this system lead to:

- improved acoustic comfort,

- reduction of the engagement force,

- no vibrations / shuddering of the lever.

TRANSMISSION OF POWER IN THE VARIOUS GEARS

First speed

The power enters from the main shaft, is transmitted to the intermediate shaft through the engagement of the 1st speed gear (assembled on the intermediate shaft).

The 3rd speed gear (assembled on the main shaft and in "neutral") allows the transmission of the power from the intermediate shaft to the layshaft and therefore to the differential thereby completing the kinematic chain for the first speed.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

Second speed

The power enters from the main shaft, is transmitted to the intermediate shaft through the engagement of the 2nd speed gear (assembled on the intermediate shaft).

The 3rd speed gear (assembled on the main shaft and in "neutral") allows the transmission of the power from the intermediate shaft to the layshaft and therefore to the differential thereby completing the kinematic chain for the second speed.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

Third speed

The drive that enters from the main shaft is transmitted directly to the layshaft and therefore to the differential through the engagement of the 3rd speed gears (assembled on the main shaft) producing the kinematic chain for the third speed.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

Fifth speed

The drive that enters from the main shaft is transmitted directly to the layshaft and therefore to the differential through the engagement of the 4th speed gears (assembled on the main shaft) producing the kinematic chain for the fourth speed.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

Fifth speed

The drive that enters from the main shaft is transmitted directly to the layshaft and therefore to the differential through the engagement of the 5th speed gears (assembled on the layshaft) producing the kinematic chain for the fifth speed.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

Reverse gear

The drive entering from the main shaft is transmitted to the layshaft by means of the kinematic chain produced by the gear for the 1st speed (assembled on the intermediate shaft in in "neutral") and that for reverse gear (assembled on the layshaft) at the time the respective synchronizer is engaged.

A - main shaft input

B - layshaft

C - intermediate shaft

D - differential output

1.9 JTD 8V, 1.9 JTD 16V · Automatic transmission

DESCRIPTION

The AISIN AF 40-6 is a 6-speed automatic transmission used on the 1.9 JTD 16V and 2.4 JTD 20V engine versions.

GENERAL SPECIFICATIONS

- Type 6-speed automatic transmission

- Engine: 1.9 JTD 16V and 2.4 JTD 20V

- Architecture: 3 clutches, 2 brakes, 1 free wheel, 2 epicyclic trains

- Hydraulic: 4 linear solenoids, 2 on/off solenoids

- Electronic: Neutral Start Switch and control unit built in, internal wiring and speed sensors

FUNCTION

Neutral control

When the vehicle stops with the lever set to "D", the clutches are automatically released and the transmission changes to neutral. In this way, the torque converter is not put under stress, there are fewer vibrations and fuel consumption is minimal.

On rough roads or on hills, the function does not activate. On hills, the transmission remains engaged to assure a hill holder effect.

Reversing control

When the gearlever is shifted from "N" to "R", reverse is not engaged if vehicle speed exceeds 11 km/h.

Adaptivity

COMPONENTS

Control unit

The control unit is fitted on the speed engagement selector and assists the gearbox and gear control lever management functions.

PIN OUT

Input/output managed by the control unit

The interface with the automatic transmission system manages information by means of the following serial networks:

C-CAN (information, data)

Diagnostic line K

Wiring

The wiring is located inside the gearbox, it is connected to the inside of the valve body:

- to the speed sensors

- to the fluid temperature sensor

- to the solenoids

The wiring is connected to the transmission control unit with an Aisin pin-to-pin connector.

Solenoid unit

The valve unit, via solenoids activated by signals from the control unit, supplies hydraulic pressure produced by the oil pump to the brakes, clutches and lock-up. Part of the fluid is also sent to lubricate the mechanical components.

1. Control unit

2. Torque converter

3. Solenoid unit

4. Brakes/clutches

5. Oil radiator

6. Oil pump

7. Epicyclic gear set

Solenoids

The linear solenoids shown in the figure control the hydraulic pressure of almost all the brakes/clutches

ON/OFF solenoid: these 2 solenoids control brake "B2" for the engine brake in first gear

Linear solenoid SLT: controls line pressure linearly on the basis of a throttle signal and engine torque

Linear solenoid SLU: controls lock-up pressure linearly in relation to:

throttle signal

engine rpm

gearbox input speed

gearbox output speed

Sensors

Lever position sensor (nsw)

The position sensor is Hall effect and is built into the control unit. It sends the gear lever position.

1. Lever position sensor

2. Control unit

Fluid temperature sensor

The fluid temperature sensor is an NTC and is integral with the wiring.

1. Oil temperature sensor

Specifications:

Speed sensors

1. Output speed sensor

2. Input speed sensor

The input speed sensor detects the input speed to the gears, i.e. the converter turbine speed.

The output speed sensor detects the rotating speed of the gear that carries drive to the differential.

1.9 JTS, 2.2 JTS · Automatic transmission

SPECIFICATIONS OF THE AISIN 55-50 SN AUTOMATIC TRANSMISSION

Compact five-speed transmission with front wheel drive

The 55-50 SN automatic transmission has a five speed gearbox with a new epicyclic gear train added to the four speed automatic gearbox, maintaining the same overall length and the same distance between the axles. It is also more compact and has a greater capacity compared with the transmission fitted on conventional vehicles.

ELECTRONIC CONTROL SYSTEM (CONTROL MODULE FOR TRANSMISSION AND ELECTRONIC COMPONENTS)

Specifications

In effect, in addition to the sophistication of the electronic control which governs the gear change strategies adapting to the style of the driver, there is the new TIP sequential alternative which allows the driver to use the vehicle in totally assisted conditions as found on conventional automatic transmissions and in manual gear change conditions with the TIP function where the intervention of the automatic function is limited to prevent incorrect or potentially damaging manoeuvres for the vehicle mechanics (the gearbox does not, for example, accept selections that would cause beyond rev conditions).

The 5 speed Aisin type gearbox, with adaptive electronic control, with dual operating possibilities (Full Auto and Trip) is controlled by means of a double control grid for the gear lever positions.

The electronic control mode adopted is the adaptive type, which means that the electronic management of the gear change is capable of analyzing the vehicle driving conditions and, after having compared them with the standard conditions memorized in its software, of selecting the operating programme (gear change law) that is best adapted to the current situation.

The system manages the following three gear change laws:

- Up hill: when driving uphill, the control unit compares the actual acceleration of the vehicle with the theoretical acceleration on a flat road, thereby determining the gradient of the road. It selects the change law and the most suitable ratio according to the gradient.

- Down hill: when the control unit detects that the vehicle is accelerating with the throttle closed (descent) and is capable of estimating that by changing down a gear the vehicle will no longer be accelerating, it changes down a gear the first time the brake is operated.

- Fast acceleration: depending on the speed with which the accelerator pedal is depressed, the control unit modifies the gear change and kick-down law.

The electronic control unit manages the operation of the automatic transmission through connection with:

the sensors/actuators fitted on the gearbox for acquiring the operating conditions and the operation of the clutches and brakes;

- the injection/ignition control unit for the exchange of information relating to the engine;

- the instrument panel for displaying the operating conditions.

ELECTRONIC COMPONENTS

Switch for start-up in neutral (nsw)

The switch for starting in neutral indicates the automatic transmission ratio, at a given time, to the starter motor, the reversing light and the automatic transmission control unit.

The switch for starting in neutral can only start the engine in "P" and in "N" (to prevent reckless driving).

The switch for starting in neutral ensures that the reversing light comes on when reverse gear is engaged.

The switch for starting in neutral can also be used to control the gear change.

- The switch for starting in neutral transmits information, making use of the circuit for the starter motor and the vehicle side reversing light directly, without going from the automatic transmission control unit.

Gearbox solenoids n 1, 2, 3, 4, 5 (s1, s2, s3, s4, s5)

The five gearbox solenoids are fitted directly on the valve casing. The solenoids can be in the ON or OFF position, depending on the control signal arriving from the automatic transmission control unit. The combined action of the five solenoids (S1, S2, S3, S4, S5) makes it possible to change the gear ratios.

Input and output speed sensor (active sensors)

The output speed sensor detects the speed of the vehicle from the number of revs of the parking gear, whilst the input speed sensor detects the input speed for the automatic transmission from the number of revs of the drum C1: both then send a signal to the automatic transmission control unit.

Difference between the active sensor and the pulse sensor

Active sensor specifications:

this sensor has an integrated Hall circuit that manages the rectangular wave signal producing energy and transmitting the signal to the automatic transmission control unit exploiting the Hall effect. The automatic transmission control unit recognizes the signal in relation to the speed of the vehicle. The specifications of the output signal are fixed and do not therefore depend on the number of revs.

- strong signal for noise

- there may also be a low number of revs (10 rpm).

Impulse sensor specifications:

- as a result of the rotation of the gear, a sinusoidal wave with an induction electro-motive force is produced, in relation to the speed of the vehicle, which is then sent to the automatic transmission control unit. The control unit converts the wave signal into an impulse signal and recognizes it in relation to the speed of the vehicle. The specifications of the output signal depend on the number of revs.

- the minimum number of revs that can be detected is 50 rpm.

Fluid temperature sensor

The oil temperature sensor is fitted directly on the valve casing which converts the temperature of the oil inside the automatic transmission into an electrical signal which is then sent to the automatic transmission control unit.

Linear pressure control solenoid (slt)

The linear pressure control solenoid controls the throttle valve by means of a signal arriving from the automatic transmission control unit in addition to the linear pressure of the clutch and the brake to reduce the shock from the gear change.

Direct control

Lock up clutch control solenoid (slu)

The lock-up clutch control solenoid controls the linear pressure of the lock-clutch by means of the signal arriving from the automatic transmission control unit in addition to the hydraulic pressure of the lock-up clutch to reduce the shock from the gear change.

Direct control:

- Engine brake: Brake B3

- Control of neutral (N): Brake B2.

Gearbox pressure control solenoid (sls)

The gearbox pressure control solenoid operates through a signal arriving from the automatic transmission control unit.

Direct control:

- control of 2nd, 3rd, 4th speeds and neutral (N): brake B1

- control of 5th speed and reverse gear: clutch C2

Transmission conductor

The switch and sensor assembly, fitted on the automatic transmission, connects the switch for starting in neutral, the solenoids S1, S2, S3, S4, S5, SLT, SLU, the input speed sensor and the oil temperature sensor to three terminals.

AUTOMATIC TRANSMISSION CONTROL UNIT PINOUT

A1 - Key lock solenoid (gear control unit)

A2 - Gearbox lock solenoid (gear control unit)

A3 - I.E.

A4 - I.E.

A5 - Open

A6 - Left door open signal

A7 - Open

A8 - Panel warning light signal

A9 - Panel warning light signal (gear control unit)

A10 - Open

A11 - Signal from diagnostic line (K line).

A12 - A.B.S.

A13 - A.B.S.

A14 - Earth (-)

A15 - Open

A16 - Open

A17 - Open

A18 - Open

A19 - Open

A20 - Open

B1 - Linear solenoid n° 5.

B2 - Input speed sensor (+).

B3 - Input speed sensor (+).

B4 - Automatic transmission solenoid unit signal

B5 - Throttle valve linear solenoid (+).

B6 - Throttle linear solenoid

B7 - Positive from battery.

B8 - Throttle valve linear solenoid (-).

B9 - Output speed sensor (-).

B10 - Input speed sensor (-).

B11 - Automatic transmission solenoid unit signal

B12 - Automatic transmission solenoid unit signal

B13 - Gear control unit signal

B14 - Gear control unit signal

B15 - Lock-up clutch linear solenoid (-).

B16 - Gearbox solenoid n° 2.

B17 - Gearbox solenoid n° 1.

B18 - Power supply

B19 - Power supply

B20 - Throttle linear solenoid

B21 - Oil temperature sensor (+).

B22 - Oil temperature sensor (-).

B23 - Automatic transmission solenoid unit signal

B24 - Gear control unit signal

B25 - Gearbox solenoid n° 4.

B26 - Gearbox solenoid n° 3.

B27 - Lock-up clutch linear solenoid (-).

B28 - Earth (-).

Automatic transmission control unit control functions

Control of the gear change and the lock-up clutch.

According to the gear change programmed, the control unit sends a signal to solenoids S1, S2, S3, S4 and S5, which are in the on/off position, to control the gear change in relation to the speed of the vehicle and the throttle valve opening.

The 55-50SN version does not have different driving modes available for the driver to select. It is basically programmed for the "economy" mode, but the automatic gear change control unit can automatically change to different programmes depending on specific circumstances.

Adaptive gearbox control by the driver (economy, medium, sports modes)

The Economy mode is used in normal driving conditions after having turned the ignition on and the driver''s wishes are ascertained by using a logic that depends on the operation of the accelerator pedal. This makes it possible to change modes and move from Economy mode (low speed) to Regular mode (average speed) or Sports mode (high speed) according to the driver''s wishes.

Uphill modes 1, 2

When the control unit detects that the vehicle is driving uphill from the engine torque and deceleration conditions, it alters the gear change strategy in relation to the gradient of the incline and avoids overloading the automatic transmission with gear changes.

Downill mode

When the control unit detects that the vehicle is driving downhill, from the increased acceleration with the accelerator completely closed, it intervenes gently on the brake changing the gear change points at high speed.

Fast control on

This control anticipates the desire of the driver to accelerate thanks to the operation of the accelerator changing down a gear only reviewing the gear change points.

Fast control in off position

This control anticipates the desire of the driver to decelerate thanks to the operation of the accelerator using the engine brake preventing a change to a higher gear.

Brake assistance control

This control anticipates the desire of the driver to decelerate thanks to the operation of the accelerator using the engine brake positively reviewing the gear change points at high speed.

Gear control on bends

This control evaluates the vehicle driving conditions round bends from the difference between the RL speed signal and the RR speed signal of the ABS, preventing a shift to higher gears, thereby ensuring the stability of the vehicle round bends.

Wusp (warm up shift pattern)

This mode warms up the engine, establishing the gear change points at a vehicle speed that is slightly higher that when the engine is cold.

Acc (adaptative cruise control)

By modifying the gear change points, this mode prevents acceleration and gear changes.

Excessive fluid temperature control

When the temperature of the oil is too high, the control unit automatically modifies the gear change arrangements. As a result, driveability is improved in low gears. In addition, the temperature of the oil and the water when decreasing, activate the lock-up clutch.

Esp (electronic stability program)

In the case of a slippery road, this mode maintains the gear engaged requiring a maintenance signal for the gear from the VDC computer and ensuring the manoeuvrability of the vehicle preventing first gear from being engaged.

Low load control µ

This mode improves traction performance during set-off in third when leaving roads with low µ

(grip coefficient) or with potholes.

Tip gear shift control (manual mode)

The driver can select the gear they prefer taking advantage of sports driving simply by moving the gear lever from "D" using the MAN+ or MAN- button. The control of the lock-up clutch is activated automatically. The control of the gear change is activated again moving from manual driving to "D".

Below is a list of the TIP mode active controls.

Authorisation to shift to higher gears

This control is activated provided that the vehicle speed exceeds the figures shown in the table below. The vehicle can start in second or in third even from stationary.

Authorisation to shift to lower gears

This control is activated to prevent the engine going outside of the rev range, provided that the speed of the vehicle does not exceed the figures given in the table below.

Automatic transfer to lower gears

This control is activated automatically according to the speeds shown in the table below.

Authorisation to shift to higher gears (if the fluid temperature is too high)

This control is activated if the temperature of the oil is high, provided that the vehicle speed exceeds the figures shown in the table below. The vehicle can start in second or in third even from stationary.

Authorisation to shift to lower gears (if the fluid temperature is too high)

If the temperature of the oil is high, this control is activated and there is a shift to a lower gear to prevent the engine going beyond the rev range.

The speed of the vehicle should not exceed the figures shown in the table below.

Lock-up clutch slip control

Slight slipping of the lock-up clutch in the release area makes it possible to extend the engagement area of the lock-up clutch at low speed, controlling the engine speed and thereby producing greater transmission efficiency and improved fuel economy.

Lock-up clutch deactivation control

This control deactivates the lock-up clutch, when shifting to a lower gear or when the engine is idling, to prevent the engine from stalling, by pressing the brake pedal at low speed.

Neutral control

When the vehicle is stopped, the automatic transmission automatically positions itself in neutral as the clutch is released, inspite of the forward gears ratio. This control makes it possible to reduce the engine load and the slipping of the torque converter, improving fuel consumption and keeping vibrations to a minimum. When the vehicle sets off, after having pressed the accelerator pedal, the clutch is engaged and the gearbox engages first speed.

If the vehicle stops uphill, there is no force due to the viscous sliding as a result of the neutral conditions set by the neutral control (N). Therefore the automatic transmission control unit operates the brkes to maintain a force equivalent to the force due to the viscous sliding.

If the control unit detects a steep incline thanks to the decrease in acceleration, the neutral control is not activated.

The automatic transmission control unit activates each linear solenoid independently of the others in the case of a neutral control:

- the SLT solenoid controls the C1 clutch directly.

- the SLS solenoid controls the B1 brake directly.

- the SLU solenoid controls the B2 brake directly.

In impulse mode, the automatic transmission control unit does not activate the neutral control.

The neutral control involves the following three processes:

- release of the clutch.

- clutch in neutral (keep in neutral).

- application of pressure.

Clutch release

The automatic transmission control unit detects that the vehicle has stopped as a result of the change in the number of revs for the clutch and sends an OFF signal to solenoid S2. The pressure of the clutch is released and the clutch releases gently. The control unit activates the hill hold function operating the brakes gently.

The automatic transmission control unit re-examines the clutch piston travel through its release time.

Clutch in neutral

The automatic transmission control unit maintains the neutral condition activating the clutch through the SLT solenoid, brake B1 with the SLS solenoid and brake B2 with the SLU solenoid. This operation reduces the clutch load and allows the vehicle to be started gently engaging the clutch again.

Application of pressure on the clutch

The automatic transmission control unit applies pressure gently, ensuring that the clutch engages when the brake pedal is released. The automatic transmission control unit also releases the pressure at brakes B1 and B2 gently and cancels the hill hold function.

Gear transfer learning control

This control learns the pressure of the clutch and the brake to reduce the shock from the gear change (shift to a higher gear, shift to a lower gear, manual shift to a lower gear, shift to a lower gear from neutral).

Learning method:

1) 65° C = < fluid temperature < 110° C.

2) Constant slight opening of the throttle valve (20-30%)

3) gear change interval (about 3 seconds)

4) repeat every gear change about 10 times.

Control of shift from n to d

This control improves the quality of the gear change from N to D by activating the SLT solenoid in relation to the travel of piston C1 learnt during the learning procedure for the change from N to D and thanks to the application of improved hydraulic pressure to the C1 clutch during the change from N to D.

Gear learning control from n to d

This control learns the hydraulic pressure C1 monitoring the engagement time of the C1 clutch and the change in the actual number of revs.

Learning method:

1) If the conditions listed above are verified.

2) If the gear change interval is more than 3 seconds.

3) Repeat the change from N to D about 10 times.

Control of shift from n to r

This control improves the quality of the gear change from N to R by activating the SLS solenoid in relation to the travel of piston C2 learnt during the learning procedure for the change from N to R and thanks to the application of improved hydraulic pressure to the C2 clutch during the change from N to R.

Gear learning control from n to r

This control learns the hydraulic pressure C2 monitoring the engagement time of the C2 clutch and the change in the actual number of revs.

Learning method:

1) If the conditions listed above are verified.

2) If the gear change interval is more than 3 seconds.

3) Repeat the shift from N to R about 10 times.

Torque reduction

This control improves the quality of the gear change sending a torque reduction request signal, from the automatic transmission, to the electronic control unit thereby reducing the drive torque during the shift from N to D and from N to R, as well as from 1st to 2nd, 3rd, 4th, 5th and viceversa.

If the accelerator pedal is pressed rapidly, this control establishes the maximum limit for the engine torque thereby preventing the engine from going beyond the rev range during the shift from 2nd to 3rd and from 3rd to 4th and viceversa and during the shift from 4th to 2nd "from clutch to clutch".

Fault diagnosis

This function continuously monitors the operation of the sensors, the solenoids and the other electronic components.

If there is a fault, the warning light in the instrument panel comes on notifying the driver of the poor operation of the automatic transmission (on board fault diagnosis).

It is only possible to locate the fault and cancel the error code and the learning value during the fault diagnosis using the FIAT tester.

Control learning method

The control learning method consists of 3 steps.

1) Warming up the engine: the temperature of the automatic transmission fluid must reach 65 - 110° C keeping the engine idling or in town driving conditions. Check the temperature using the diagnostic equipment.

DO NOT CARRY OUT THE STALL TEST to increase the temperature of the automatic transmission fluid.

The learning of the control is only possible when the temperature of the automatic transmission fluid is between 65° C and 110° C.

2) Learning of the control for the shift from N to D or from N to R: keep the vehicle stationary applying the brake. Change from N to R and keep R engaged for more than 3 seconds, then return to N. Repeat the gear change from N to R and the one from N to D five times.

3) Learning the control for shifting to a higher or lower gear: accelerate until 50 km/h is reached in 5th with a throttle opening of 15-20% in "D". Decelerate applying the brake until the vehicle stops. (More than 14 seconds must elapse between the start of the deceleration and the stopping). Repeat the procedure ten times.

After having replaced the automatic transmission or the automatic transmission control unit or after having updated the software, the control learning data should be cancelled and the learning procedure carried out again.

Hydraulic control system

On the basis of the hydraulic pressure produced by the oil pump, the control unit sends a signal to the solenoid and the hydraulic control system manages the hydraulic pressure acting on the torque converter, the epicyclic gear train, the clutches and the brakes in relation to the specifications listed below.

GEAR SELECTOR LEVER

Operation

The gear selector lever can be operated according to two different grids in relation to the gearbox operating mode.

Full auto mode

In this completely automatic gearbox operating mode the lever moves along the right part of the grid in accordance with the usual positions for automatic tansmissions:

- P, park;

- R, reverse;

- N, neutral;

- D, drive.

Tip mode

When the selector lever is moved to the left section of the grid the gearbox operates according to the TIPTRONIC mode with the selection of the gears entrusted to the manual intervention of the driver who by pushing the lever forward goes up a gear and by pulling it backward changes down.