Dodge Durango (DN). Manual — part 36

IMPELLER

The impeller (Fig. 10) 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 con-
verter housing is rotated by the engine, so is the
impeller, because they are one and the same and are
the driving member of the system.

Fig. 10 Impeller

1 – ENGINE FLEXPLATE
2 – OIL FLOW FROM IMPELLER SECTION INTO TURBINE

SECTION

3 – IMPELLER VANES AND COVER ARE INTEGRAL

4 – ENGINE ROTATION
5 – ENGINE ROTATION

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DESCRIPTION AND OPERATION (Continued)

TURBINE

The turbine (Fig. 11) is the output, or driven, mem-

ber 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 tur-
bine. The design of the turbine is similar to the
impeller, except the blades of the turbine are curved
in the opposite direction.

Fig. 11 Turbine

1 – TURBINE VANE
2 – ENGINE ROTATION
3 – INPUT SHAFT

4 – PORTION OF TORQUE CONVERTER COVER
5 – ENGINE ROTATION
6 – OIL FLOW WITHIN TURBINE SECTION

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DESCRIPTION AND OPERATION (Continued)

STATOR

The stator assembly (Fig. 12) is mounted on a sta-

tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 13).
The stator contains an over-running clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the over-run-
ning clutch, the torque multiplication feature of the
torque converter is operational.

TORQUE CONVERTER CLUTCH (TCC)

The TCC (Fig. 14) was installed to improve the

efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock–free power transfer, it
is natural for all fluid couplings to slip. If the impel-
ler and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston was added to the turbine, and a friction mate-
rial was added to the inside of the front cover to pro-
vide this mechanical lock-up.

OPERATION

The converter impeller (Fig. 15) (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.

TURBINE

As the fluid that was put into motion by the impel-

ler blades strikes the blades of the turbine, some of

Fig. 12 Stator Components

1 – CAM (OUTER RACE)
2 – ROLLER
3 – SPRING
4 – INNER RACE

Fig. 13 Stator Location

1 – STATOR
2 – IMPELLER
3 – FLUID FLOW
4 – TURBINE

Fig. 14 Torque Converter Clutch (TCC)

1 – IMPELLER FRONT COVER
2 – THRUST WASHER ASSEMBLY
3 – IMPELLER
4 – STATOR
5 – TURBINE
6 – FRICTION DISC

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DESCRIPTION AND OPERATION (Continued)

the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine’s blades it con-
tinues in a “hindering” direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.

STATOR

Torque multiplication is achieved by locking the

stator’s over-running clutch to its shaft (Fig. 16).
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over–run-
ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a “helping”
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.4:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock–up is no longer doing so. In this con-

dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.

Fig. 15 Torque Converter Fluid Operation

1 – APPLY PRESSURE
2 – THE PISTON MOVES SLIGHTLY FORWARD

3 – RELEASE PRESSURE
4 – THE PISTON MOVES SLIGHTLY REARWARD

Fig. 16 Stator Operation

1 – DIRECTION STATOR WILL FREE WHEEL DUE TO OIL

PUSHING ON BACKSIDE OF VANES

2 – FRONT OF ENGINE
3 – INCREASED ANGLE AS OIL STRIKES VANES
4 – DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING

AGAINST STATOR VANES

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DESCRIPTION AND OPERATION (Continued)