Case 580SR Service Manual page 178

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112 SECTION 21 - TRANSMISSION
THE CONVERTER AND PUMP DRIVE SECTION
Engine power is transmitted from the engine fly-
wheel to the impeller through the impeller cover.
This element is the pump portion of the torque con-
verter and is the primary component which starts the
oil flowing to the other components which results in
torque multiplication. This element can be compared
to a centrifugal pump in that it picks up fluid at its
centre discharges at its outer diameter.
The torque converter turbine is mounted and dis-
charge opposite the impeller and is connected to the
turbine shaft or directional clutch shaft.
This element receives fluid at its outer diameter and
discharges at its centre.
The stator of the torque converter is located be-
tween and at the centre of the inner diameters of the
impeller and turbine elements. Its function is to take
the fluid which is exhausting from the inner portion of
the turbine and change its direction to allow correct
entry for recirculation into the impeller element.
This recirculation causes the converter to multiply
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torque.
The converter and pump drive section
The converter will multiply engine torque to its de-
signed maximum multiplication ratio when the tur-
bine shaft is at zero RPM (stall).
Therefore we can say that as the turbine shaft is de-
creasing in speed, the torque multiplication is in-
creasing.
In the impeller cover a splined shaft is fitted which
runs inside and through the turbine shaft to drive a
hydraulic pump which is fitted at the back of the
transmission.
Since the shaft is connected to the centre of the im-
peller cover, the pump speed will be the same as en-
gine speed.
The rear side of the impeller cover has a tanged drive
which drives the transmission charging pump locat-
ed in the converter housing. The transmission charg-
ing pump speed is also the same as the engine
speed.