Jeep cherokee 2000 Service Manual page 1134

21 - 226 AW–4 AUTOMATIC TRANSMISSION
DESCRIPTION AND OPERATION (Continued)
1 – APPLY PRESSURE
2 – THE PISTON MOVES SLIGHTLY FORWARD
(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 vanes it contin-
ues 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
clutch to its shaft (Fig. 12). Under stall conditions
(the turbine is stationary), the oil leaving the turbine
vanes strikes the face of the stator vanes and tries to
rotate them in a counterclockwise direction. When
this happens the over–running clutch of the stator
locks and holds the stator from rotating. With the
stator locked, the oil strikes the stator vanes and is
redirected into a "helping" direction before it enters
the impeller. This circulation of oil from impeller to
turbine, turbine to stator, and stator to impeller, can
produce a maximum torque multiplication of about
2.2:1. 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 condition of operation, the stator begins to
free wheel and the converter acts as a fluid coupling.
Fig. 11 Torque Converter Fluid Operation
3 – RELEASE PRESSURE
4 – THE PISTON MOVES SLIGHTLY REARWARD
Fig. 12 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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