Ranger 4WD V6-3.0L VIN U (1997)
Torque Converter: Description and Operation
DESCRIPTION
The 4R44E uses a four element torque converter. The converter contains the standard internal components (turbine, impeller, and stator) for transfer
of power and multiplication of torque. It also utilizes a disc type torque converter clutch (TCC) for maximum fuel economy.
OPERATION
The operation of the main torque converter components is as follows:
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The converter cover and impeller are connected to the engine crankshaft. Rotation of the cover and impeller by the engine crankshaft sets the fluid
in motion.
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The turbine reacts to the fluid motion from the impeller, transferring rotation to the geartrain by way of the turbine shaft.
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The stator redirects the fluid going back to the impeller, from the turbine. By directing fluid back to the impeller in the same direction as engine
rotation the stator multiplies engine torque.
When applied, the TCC provides a mechanical link between the converter turbine and the engine, allowing for a direct mechanical power transfer from
the engine to the transmission. The converter clutch pressure plate is applied and released by fluid pressure, which is controlled by the powertrain
control module (PCM). The PCM controls the torque converter clutch using a pulse-width modulated TCC solenoid.
Impeller and Cover
The impeller sets the fluid in motion and directs it to the turbine. The impeller is welded to the converter cover.
Turbine
The turbine is the driven member of the converter. It is driven by fluid from the impeller and transfers the hydraulic power to the transmission.
When the converter lockup clutch is engaged, the power is transferred mechanically.
Reactor
The reactor is equipped with heavily curved vanes and its center hub has an one-way clutch which prevents the stator from rotating opposite to the
engine rotation. The reactor reverses the fluid and returns it to the impeller in the direction of impeller rotation. The one-way clutch prevents the
force of this fluid from turning the stator against the impeller and turbine.
