Ford Galaxy / Ford S-MAX. Manual - part 483

Transmission components

Ravigneaux planetary gearset

One of the special features of the AWF21 transmission is its Ravigneaux planetary gearset.

The Ravigneaux planetary gearset has the following features:

It offers the possibility of more gears than a conventional planetary gearset.
Compact design (space-saving) in relation to the available transmission ratios.
Two sun gears with different diameters
Two sets of planetary gears - inner and outer. The inner planetary gears are in constant
mesh with the smaller, rear sun gear and with the outer planetary gears. The outer
planetary gears are in constant mesh with the ring gear and the larger, front sun gear.
The planetary gears are all fitted on a joint planetary gear holder.

Operation

The transmission ratios are achieved via the following combinations of locked and/or
coupled components. The table shows the principle of obtaining a high ratio (1), a low ratio

5th

0,859

2,86

3,22

6th

0,686

2,28

2,57

Reverse

3,394

11,30

12,73

Item

Component

C2 clutch

B2 brake

F1 freewheel

Front planetary gearset

C1 clutch

B1 brake

C3 clutch

TORQUE CONVERTER

Differential unit

Driven gear wheel of the intermediate stage

Driving gear wheel of the intermediate stage

Ravigneaux planetary gear set

Turbine shaft

(6) and a reverse rotation (i.e. reverse gear with a high ratio).

Description

Ring gear

Long planet gear

Small planet gear

Short planet gear

Transmission input shaft

Large sun gear

On the AWF21 transmission the Ravigneaux planetary gearset is connected in series with a
conventional planetary gearset. The conventional planetary gearset can generate a speed
reduction on the two sun gears of the Ravigneaux planetary gearset for gears 1 to 5 and for
reverse gear.

Electrical control

The following components are part of the control system for the automatic
transmission:

TCM. Controls activation and deactivation of the solenoid valves by processing the input
signals from, among others the speed sensor and rotational speed sensor of the
transmission, as well as the temperature sensor. It also saves adaptive data, DTCs and
frozen values for diagnosis.
Gearshift position sensor, integrated in the TCM.
Solenoid valves S1 and S2. Primarily control engine braking in 1st gear.
Solenoid valve SLU. Controls the lockup function, and is also used during certain
gearshift processes.

Item

Gear / ratio

Input torque

Locked

Output torque

Small sun gear

Planetary gear holder

RIng gear

Small sun gear

Large sun gear

RIng gear

Small sun gear and large sun gear

No component

Ring gear

Small sun gear and planetary gear holder

No component

Ring gear

Large sun gear and planetary gear holder

No component

RIng gear

Planetary gear holder

Large sun gear

RIng gear

Reverse.

Large sun gear

Planetary gear holder

RIng gear

Part Number

Solenoid valve SLT. Controls the transmission system pressure.
The solenoid valves SLC1, SLC2 and SLC3 control which clutches are used.
Solenoid valve SLB1. Controls the use of brake B1.
Rotational speed sensor, input shaft
Output shaft rotational speed sensor
Oil temperature sensor
GSM (Gear Selector Module), in the gear selector housing. Provides information to the
TCM about the desired driving mode, etc. Shift select mode and sport mode W.
Hydraulic system with oil pump, torque converter, hydraulic control housing and oil
cooler.
A front planetary gearset and a rear planetary gearset, the transmission ratios of which
are controlled by clutches and brakes.

Solenoid valves

Item

Component

Oil temperature sensor

Solenoid valve SLU

Solenoid valve SLC3

Solenoid valve SLB1

Input shaft rotational speed sensor

Output shaft rotational speed sensor

Solenoid valve S1

Solenoid valve S2

Solenoid valve SLT

Solenoid valve SLC2

Solenoid valve SLC1

transmission control module

Automatic Transmission/Transaxle -
Vehicles With: 6-Speed Automatic
Transaxle - AWF21 - Automatic
Transmission

S-MAX/Galaxy 2006.5 (02/2006-)

Diagnosis and Testing

Construction features, transmission differential side

WARNINGS:

The ESD protection measures must be adhered to without fail, as otherwise the

transmission electronics could be destroyed.

Electrical connectors to and from the automatic transmission control electronics must

only be separated or connected when no voltage is present.

Because of bodily electrostatic charge, connectors must not be disturbed, as this may

cause damage to the transmission control electronics.
NOTE: In order for the diagnosis of the automatic transmission to be meaningful, all other
systems such as the PCM, IC and ABS must be operating correctly, because through the
CAN databus they may have an effect on the TCM and therefore on the transmission
control.
NOTE: Electrical faults which appear - even only momentarily - when the ignition is
switched on, will be stored in the fault memory of the relevant control unit and may have
effects on the control system. Loose connections and fuses or connectors which have
been removed or disconnected for testing purposes all count as electrical faults.

Introduction

WARNING: Adhere to the ESD protection measures listed below without fail, as

otherwise the transmission control electronics could be destroyed
NOTE: Always take into account TSBs and OASIS messages.
NOTE: Do not take any short cuts or assume that critical checks or adjustments have
already been made.
NOTE: Follow the test procedure described in the WDS/IDS exactly. In this way, test
steps or important component tests are prevented from being overlooked.

Troubleshooting an electronically controlled automatic transaxle is simplified by using the
proven method of diagnosis. One of the most important things to remember is that there is
a definite procedure to follow.

Details of ESD protection

When dealing with the mechatronics, for example during a repair, suitable protective
measures must be taken, especially ESD protection.

The term ESD means: Electro Static Discharge.

A person who is electrostatically charged and not earthed carries a voltage field with them,
and so endangers "electrostatically sensitive components" which are contained in the
control electronics. Carelessness when working on the transmission, touching the contacts
of the central connector with the hand or making measurements using a multimeter will
destroy the control electronics.

Preliminary inspection

NOTE: Many concerns with an automatic transmission are caused by incorrect operating
conditions or operating error on the part of the driver. It is therefore very important to
include the environment when making a diagnosis.

Apply the parking brake and move the selector lever to the "P" position when:

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