26—TORQUE-FLITE TRANSMISSION
CHRYSLER SERVICE MANUAL
plished by a differential area which is subjected
to supply pressure when, the valve is upshifted.
When the valve is upshifted, throttle pressure
is cut off so that normal downshifts are not
throttle sensitive.
e. 2-3
Shift Valve
This shift valve automatically shifts the trans-
mission from intermediate to direct gear. The
2-3 shift valve train is similar in construction
and operation to the 1-2 shift valve train, in
that it is controlled by governor and throttle
pressures and spring force. When the valve
train is in the upshifted position, oil is fed by
line pressure through metering hole "A" to the
following places:
(1) 3-1 relay valve.
(2) Through or around metering hole "E"
(depending on shuttle valve position) to the
"off" area of the kickdown servo and through
the ball check valve to the rear clutch piston.
With the shift valve downshifted (at the ex-
treme of travel toward the governor pressure
end of the rear valve body) any oil in the rear
clutch chamber and the kickdown servo "off"
area is allowed to escape through the vent port.
f. 3-1 Relay Valve
This valve obtains a 3-1 downshift. The 3-1
relay valve is a valve arranged so that the 2-3
shift valve is coupled to the 1-2 shift valve dur-
ing downshift at light throttle. Under these con-
ditions, line pressure from the 2-3 shift valve
acting on the 3-1 relay valve overcomes the
forces of throttle and spring pressure moving
the valve to the throttle pressure end. In this
position, line pressure from the 1-2 shift valve
is permitted to act on the governor plug end of
the 2-3 shift valve holding the 2-3 shift valve
in the upshift position regardless of governor
pressure.
As car speed decreases and governor pressure
can no longer overcome the force of the 1-2 shift
valve spring, the 1-2 shift valve will downshift,
cutting off the line pressure to the 3-1 relay
valve. This will permit the two shift valves to
downshift at the same time resulting in a
smooth 3-1 downshift.
g. Kickdown Valve
The kickdown valve makes possible a forced
downshift from direct to second—second to
breakaway and direct to breakaway by depress-
ing the accelerator pedal past the detent "feel"
near wide open throttle.
It is desirable to limit the maximum vehicle
speed at which kickdown may be made (ap-
proximately 70 mph. from drive to second and
approximately 30 mph. from drive or second
to breakaway). The throttle pressure actuated
kickdown detent plug on the stem of the kick-
down valve, supplies the resistance necessary
for a detent "feel" at kickdown. With the kick-
down valve in the kickdown position, throttle
pressure is routed to the following places:
(1) Through ball check valve to the 1-2 shift
valve kickdown plug.
(2) Through ball check valve to the 2-3 shift
valve kickdown plug.
This pressure, when applied to the end of the
kickdown plugs, is great enough to make the
shift valves downshift against the force of any
governor pressure up to the kickdown limit
speeds.
h. Shuttle Valve, Shuttle Valve Plug,
and Servo Pressure Bleed Valve
The shuttle valve has two separate functions
and performs each independently of the other.
The first is that of providing fast release of the
kickdown band, and delayed smooth rear clutch
engagement when the driver makes a "lift-foot"
upshift from second to direct.
The "lift-foot" upshift is "made by acceler-
ating the vehicle in breakaway or second gear
and then returning the accelerator pedal to
closed throttle. Without the shuttle valve, the
resulting upshift to direct would consist of a
series of lurches, caused first by the braking
effect on the vehicle by the second gear ratio
and then by the harsh engagement of the rear
clutch.
Under conditions of closed throttle (no throt-
tle pressure) and moderate vehicle speed (mod-
erate governor pressure) the shuttle valve and
shuttle valve plug are forced to their extreme
of travel (toward the throttle pressure end of
the shuttle valve plug). In this position, oil is
allowed to flow from the kickdown servo apply
pressure port to the rear clutch pressure port
and kickdown servo "off" area. Because the
line pressure apply area of the kickdown servo
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