CHRYSLER SERVICE MANUAL
TOROUE-FLITE TRANSMISSION—21
In a general way, the components of any
automatic control system may be grouped into
the following basic components or units:
(1) The pressure supply system.
(2) The clutches and band servos.
(3) The pressure regulating valves.
(4) The flow control valves.
Taking each of these basic components or
units in turn, the control system may be de-
scribed as follows:
5.
THE PRESSURE SUPPLY SYSTEM
a. Front Pump
Under all normal operation conditions (up to
a forward speed of approximately 35 mph.) the
front pump, driven at engine speed, provides
oil needed for torque converter pressure, con-
trol pressures, and lubrication.
The front pump delivers oil at regulated
pressure of approximately 90 psi. to fulfill
these conditions and also satisfy the normal
amount of internal leakage in the transmission
at all engine speeds above approximately 700
rpm. In reverse, the front pump regulated pres-
sure is increased to approximately 225 psi. in
order to handle the high torque loads imposed
during reverse operation.
b.
Rear Pump
The rear pump (smaller than the front pump
and driven by the output shaft) furnishes all
of the oil required by the transmission in nor-
mal driving at all vehicle speeds above approxi-
mately 35 mph. Rear pump oil pressure is
routed to the regulator valve body through a
drilled passage in the transmission case. The
front clutch and low-reverse band are applied
by the oil pressure developed by the rear pump
when the engine is started by pushing.
6. CLUTCHES AND BAND SERVOS
a. Front Clutch
The front clutch transmits full engine and con-
verter torque in all forward drive positions.
The front clutch piston is moved hydraulically
to engage the multiple disc clutch in all forward
speeds. The clutch piston is released by means
of the clutch return spring when feed of the
control pressure is discontinued.
In order to develop the required capacity, a
system of levers is used to actuate the clutch
apply plate.
Although no pressure is applied to the front
clutch piston in reverse or neutral, oil is present
in the clutch piston chamber. With high rota-
tive speeds of the clutch retainer in reverse or
neutral, it is possible to build up sufficient cen-
trifugal oil pressure to move the clutch piston.
To eliminate the possibility of clutch drag caus-
ed by such movement, the clutch check valve
ball is unseated by centrifugal force and the oil
in the chamber is allowed to escape. For normal
application of the clutch, the flow of oil under
controlled pressure into the clutch piston cham-
ber is sufficient to seat the clutch check valve
ball.
b.
Rear Clutch
The rear clutch locks the gear train for direct
drive operation in the forward range, and also
transmits full input torque to the gear train
in reverse operation. Rear clutch operation is
similar to that of the front clutch, except that
no levers are used. When making the power
upshift from second to direct, the engagement
of the clutch and disengagement of the kick-
down band is accomplished by application of
controlled pressure.
c. Kickdown Servo
The kickdown piston actuates the kickdown
band through the kickdown lever, strut, and
anchor, holding the sun gear of the rear plane-
tary set stationary and resulting in a forward
ratio of 1.45 to 1 through the rear planetary
gear set. The kickdown piston is hydraulically
applied in 2 (second) and D (drive) second
(kickdown) by two controlled pressures—line
pressure and throttle compensated pressure-
acting on separate areas.
In N (neutral), 1 (low), D (drive) break-
away, and R (reverse) the kickdown piston is
held released by the kickdown piston spring,
there being no pressures applied to the kick-
down piston at these times. In the D (drive)
range, for the automatic upshift from second to
direct drive, the kickdown piston is released
by controlled pressure acting on the "off" area
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