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7-50
GROUP 7-AUTOMATIC TRANSMISSION
FIG. 16
- Intermediate
Servo and Band
PRESSURE
~.PPL
Y
PRESSURE
RELEASE
SIDE OF
PISTON
SCREW
D1485-A
FIG.
17
- Low-Reverse Servo and Band
carrier is rotating at a slower speed
than the ring
gear. Therefore, the
low
gear ratio (torque multiplica-
tion) is a combination of
the ratios
provided
by the
forward
and reverse
planet assemblies.
Power Flow Intermediate Gear.
In intermediate gear (Fig.
18), the
forward clutch is
applied and the
intermediate
band
is holding
the
reverse high
clutch
drum, input
shell and sun
gear from
turning.
The
power
flow is
through the
input shaft into
the forward clutch
and forward front
planet assembly
ring
gear.
The
sun
gear is held from
rotating by
the intermediate
band.
This
causes
the forward planet
pinions to
rotate
(walk)
around
the
sun
gear, carrying the forward
planet carrier
with
them. The for-
ward planet
carrier,
being
splined
to
the output shaft,
causes
clock-
wise
rotation
of
the
output shaft at
a reduction in speed compared
to
the
speed of
the
input shaft,
and at
an increase
in torque.
Clockwise rotation of the output
shaft causes clockwise rotation of
the output shaft ring gear, causing
the reverse planet pinions to also
rotate (walk) around the sun gear
in a clockwise direction. The reverse
planet carrier will also rotate clock-
wise and the one-wav clutch inner
race being splined to the reverse
planet carrier, will overrun.
Power Flow High Gear. In high
gear (Fig. 18), the forward and re-
verse-high clutches are applied. The
power flow is through the input
shaft into the
for~ard
clutch cylin-
der. (The forward clutch cylinder
rotates the steel clutch plates of the
forward clutch and the composition
c1utch plates of the reverse-high
clutch.) The forward clutch directs
the power flow through the forward
clutch hub and ring gear to the
forward planet carrier.
The reverse-high clutch directs
the power flow through the input
shell to the sun gear. With the sun
gear and the forward clutch hub
ring gear driven at the
same
speed
the forward planet assembly (that
is splined to the output shaft) is
forced to rotate the output shaft at
the same speed and direction to
provide high gear.
Power Flow Reverse. In reverse
(Fig. 18), the reverse-high clutch and
low-reverse band are applied. The
power flow is through the input
shaft, reverse-high clutch, input
shell
and to the
sun
gear. Clockwise
rotation of the
sun
gear causes
counter-clockwise rotation of the
reverse planet gears.
The low-reverse band, holding
the low-reverse drum and reverse
planet carrier from turning, causes
the reverse planet gears to rotate
counter-clockwise.
This rotates the reverse ring gear
and hub countc:r-clockwise. The hub
splined to the output
shaft
rotates
the output
shaft
counter-clockwise
at a reduction
in speed
and at an
increase in torque for reverse gear.
HYDRAULIC CONTROL
SYSTEM
FRONT PUMP
A gear type ;:mmp mounted on
the front of the transmission case
supplies the fluid for the operation
of the hydraulic control system.
Pump intake is through a screen
which is part of the main control
assembly and into the case casting
and pump. Discharge is through
the case into the main control as-
sembly. Fluid from the front pump
is directed to the following valves
in the main control assembly:
Main Oil Pressure Regulator
Valve
Manual Valve
Throttle Booster Valve
2-3 Shift Valve
Fluid is also directed to the
primary throttle valve, which is
located in the rear of the
case. Fluid
pressure delivered to these
valves
is
at a pressure controlled by the main
oil pressure regulator
valve.
MAIN OIL PRESSURE
REGULATOR VALVE
The main regulator valve assem-
bly consists of the main oil pressure
regulator valve and spring, main
oil pressure booster valve, spring
and sleeve, located in one bore in
the mi!-in control
assembly
(Fig. 20).
Fluid is delivered to the
end
and
one valley of the main regulator
valve from the
front
pump. Fluid
pressure on the end land tends to
move the valve against spring force.
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