Dodge Ram Truck 1500-2500-3500. Manual — part 1685

IMPELLER

The impeller is an integral part of the converter housing. The impeller consists of curved blades placed radially
along the inside of the housing on the transmission side of the converter. As the converter housing is rotated by the
engine, so is the impeller, because they are one and the same and are the driving members of the system.

Impeller

1 - ENGINE FLEXPLATE

4 - ENGINE ROTATION

2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION

5 - ENGINE ROTATION

3 - IMPELLER VANES AND COVER ARE INTEGRAL

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TURBINE

The turbine is the output, or driven, member of the converter. The turbine is mounted within the housing opposite
the impeller, but is not attached to the housing. The input shaft is inserted through the center of the impeller and
splined into the turbine. The design of the turbine is similar to the impeller, except the blades of the turbine are
curved in the opposite direction.

Turbine

1 - TURBINE VANE

4 - PORTION OF TORQUE CONVERTER COVER

2 - ENGINE ROTATION

5 - ENGINE ROTATION

3 - INPUT SHAFT

6 - OIL FLOW WITHIN TURBINE SECTION

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STATOR

The stator assembly is mounted on a stationary shaft
which is an integral part of the oil pump. The stator (1)
is located between the impeller (2) and the turbine (4)
within the torque converter case.

The stator contains an over-running clutch (1-4), which
allows the stator to rotate only in a clockwise direction.
When the stator is locked against the over-running
clutch, the torque multiplication feature of the torque
converter is operational.

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TORQUE CONVERTER CLUTCH (TCC)

The TCC was installed to improve the efficiency of the
torque converter that is lost to the slippage of the fluid
coupling. Although the fluid coupling provides smooth,
shock-free power transfer, it is natural for all fluid cou-
plings to slip. If the impeller (3) and turbine (5) were
mechanically locked together, a zero slippage condi-
tion could be obtained. A hydraulic piston (6) with fric-
tion material (7) was added to the turbine assembly
(5) to provide this mechanical lock-up.

In order to reduce heat build-up in the transmission
and buffer the powertrain against torsional vibrations,
the TCM can duty cycle the L/R-CC Solenoid to
achieve a smooth application of the torque converter
clutch. This function, referred to as Electronically Mod-
ulated Converter Clutch (EMCC) can occur at various
times depending on the following variables:

•

Shift lever position

•

Current gear range

•

Transmission fluid temperature

•

Engine coolant temperature

•

Input speed

•

Throttle angle

•

Engine speed

OPERATION

The converter impeller (driving member), which is integral to the converter housing and bolted to the engine drive
plate, rotates at engine speed. The converter turbine (driven member), which reacts from fluid pressure generated
by the impeller, rotates and turns the transmission input shaft.

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