Buick LeSabre 1965 Service Manual page 220

5 - 6 DESCRIPTION & OPERATION
SUPER TURBINE "300'
smooth operation. It functions as
a fluid coupling at normal road
load conditions and at higher
speeds. Description of transmis-
sion is divided into six (6) basic
sections: (1) Torque Converter,
(2) Oil Pump, (3) Planetary Gear
Set and Controls, (4) Reverse
Clutch, (5) Governor, (6) Valve
Body.
1. Torque Converter
The torque converter is connected
to the engine flywheel and serves
as a hydraulic coupling through
which engine torque is trans-
mitted to the input shaft. The
torque converter steps up or mul-
tiplies engine torque whenever
operating c o n d i t i o n s demand
greater torque than the engine
alone can supply. The torque con-
verter consists of three (3) basic
sections: (a) Converter Pump,
(b) Variable Pitch Stator, (c) Con-
verter Turbine.
a. Converter Pump
The f u n c t i o n of the converter
pump is to convert engine torque
into an energy transmitting flow
of oil to drive the converter tur-
bine into which the oil is pro-
jected. The c o n v e r t e r pump
operates as a centrifugal pump,
picking up oil as its center and
discharging the oil at its rim.
However, the converter is shaped
to discharge the oil parallel to
its axis in the form of a spinning
hollow cylinder. See Figure 5-2.
b. Variable Pitch Stator
The variable pitch stator is lo-
cated between the converter tur-
bine and the converter pump, and
is supported by the stator shaft.
The stator is equipped with a free
wheel clutch assembly. When the
clutch assembly is held station-
ary, it changes the direction of
oil flow from the turbine to the
proper angle for smooth entrance
into the converter pump. As the
turbine approaches pump speed
the direction of oil flow changes
until it no longer opposes pump
rotation. The stator then free
wheels so that it will not interfere
with the flow of oil between the
turbine and converter pump. For
normal operation in Drive range
the stator blades are set at low
angle. For increased accelera-
tion and performance, torque may
be obtained by setting the stator
blades at high angle. See Figure
5-3.
c. Converter Turbine
The function of the converter tur-
bine is to absorb energy from the
oil projected into it by the pump
and convert the energy into torque
and transmit that torque to the
input shaft. See Figure 5-4.
2. Oil Pump
A positive displacement internal-
external gear type oil pump is
used to supply oil to fill the con-
verter, for engagement of forward
and reverse clutches for applica-
tion and release of the low band
and to circulate oil for lubri-
cation and heat transfer. See
Figure 5-5.
3. Planetry Gear Set and
Controls
The planetary gear set consists
of an input sun gear, low sun
gear, short and long pinions, a
reverse ring gear and a planet
carrier. The input sun gear is
splined to the input shaft. The
low sun gear, which is part oi
the forward clutch assembly, may
revolve freely until the low band
is applied. The input sun gear is
in mesh with three (3) long pin-
ions and the long pinions are in
mesh with three (3) short pinions.
The short pinions are in mesh
with the low sun gear and reverse
ring gear. The input sun gear and
short pinions always rotate in the
same direction. Application of
either the low band or the reverse
clutch determines whether the
output shaft rotates forward or
backward. See Figure 5-6.
a. Forward Clutch
The forward clutch assembly con-
sists of a drum, piston, springs,
piston seals, and a clutch pack.
These parts are retained inside
the drum by the low sun gear and
flange assembly and retainer
ring. When oil pressure is ap-
plied to the piston, the clutch
plates are pressed together con-
necting the clutch drum to the
input shaft through the clutch hub.
This engagement of the clutch
causes the low sun gear to rotate
with the input shaft. See Figure
5-7.
b. Low Band
The low band is a double-wrap
steel band faced with a bonded
lining which surrounds the for-
ward clutch drum. The band is
hydraulically applied by the low
servo piston, and released by
spring pressure. See Figure 5-7.
4. Reverse Clutch
The reverse clutch assembly con-
sists of a piston, inner and outer
seal, cushion spring, coil springs,
clutch pack, and pressure plate.
These parts are retained inside
the case by a retaining snap ring.
When oil pressure is applied to
the piston, the clutch plates are
pressed together holding the re-
verse ring gear stationary. This
engagement of the clutch causes
reverse rotation of the output
shaft. See Figure 5-8.
5. Governor
The governor is l o c a t e d to the
rear of the transmission case on
the left side and is driven off the
output shaft. The purpose of the
governor is to generate a speed