Ford Workshop Service and Repair Manuals

It has the following features:

• Two planetary gearsets, one of which is designed as a Ravigneaux gearset
• Shift Select as standard
• Gear position sensor integrated in the TCM (transmission control module)
• Drivers can choose between normal and sport mode gearshift programs.
• A total of 8 solenoid valves to control the hydraulic circuit.
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  6 solenoid valves to control the gearshift progress.
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  1 solenoid valve to control the lockup function of the torque converter.
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  1 solenoid valve to control the system pressure.
• In 1st, 2nd and reverse gear the engine torque is limited to 400 Nm.
• The maximum permitted torque at the input shaft of the transmission behind the converter is 700 Nm when a forward gear is engaged (D or Shift Select) and 600 Nm when reverse is engaged.
• Oil capacity of 7 litres. The oil level on the 2.0L Duratorq (DW) diesel application is checked through an overflow pipe, and on the 2.3L Duratec-HE (MI4) application, it is checked using a conventional engine oil dipstick.
• Weight: 94 kg.

Transmission ratios in the individual gears:

Gear	Transmission Ratio
	Without end stage	Incl. end stage for (DW) diesel	Incl. end stage for 2.3L MI4
First	4,148	13,81	15,56
Second	2,370	7,89	8,89
Third	1,556	5,18	5,4
Fourth	1,155	3,85	4,33
5th	0,859	2,86	3,22
6th	0,686	2,28	2,57
Reverse	3,394	11,30	12,73

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

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.
• 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