Buick LeSabre 1965 Service Manual page 292

5 - 7 8 . DESCRIPTION & OPERATION
SUPER TURBINE "400'
Location
Solenoid Assembly to Case
Valve Body to Case
Pump Body to Cover
Pump Body to Cover
Pump Assembly to Case
Rear Servo Cover to Case
Governor Cover to Case
Parking Brake Bracket to Case . . .
Vacuum Modulator Retainer to Case
Valve Body to Case
Oil Pan to Case
Case Extension to Case
Thread
Size
1/4-20
1/4-20
5/16-18
5/16-18
5/16-18
5/16-18
5/16-18
5/16-18
5/16-18
5/16-18
5/16-18
3/8-16
Torque
Ft. Lbs.
6-10
6-10
15-20
15-20
15-20
15-20
15-20
15-20
15-20
6-10
10-13
20-25
5-2 DESCRIPTION AND
MECHANICAL
OPERATION
The Super Turbine Automatic 400
Transmission, is a fully auto-
matic unit consisting primarily of
a 3-element hydraulic torque con-
verter and a compound planetary
gear set. Three multiple - disc
clutches, two sprag units, and two
bands provide the friction ele-
ments required to obtain the de-
sired function of the compound
planetary gear set.
The 3-element torque converter
consists of a pump, turbine and a
variable pitch stator assembly.
The stator blades can be operated
in two different positions, maxi-
mum or high angle and minimum
or low angle. The s t a t o r is
mounted on a one way r o l l e r
clutch which will allow the stator
to turn c l o c k w i s e but not
counterclockwise.
The torque converter housing is
filled with oil and is attached to
the engine crankshaft by a fly-
wheel, thus always rotates at en-
gine speed. The converter pump
is an integral part of the con-
verter housing, therefore the
pump blades, rotating at engine
speed, set the oil within the con-
verter into motion and direct it
to the turbine, causing the turbine
to rotate.
As the oil passes through the
turbine it is traveling in such a
direction that if it were not re-
directed by the stator it would
hit the rear of the converter pump
blades and impede its pumping
action. So at low turbine speeds,
the oil is redirected by the stator
to the converter pump in such a
manner that it actually assists the
converter pump to deliver power,
or multiply engine torque.
High stator blade angle means
greater redirection of the oil and
increased engine speed and torque
multiplication for maximum per-
formance. At engine idle it re-
duces the e f f i c i e n c y of the
converter which reduces "creep".
Low angle results in a more effi-
cient converter for c o u p l i n g
operation.
As turbine speed increases, the
direction of the oil leaving the
turbine changes and flows against
the rear side of the stator vanes
in a clockwise direction. Since
the stator is now impeding the
smooth flow of oil, its roller
clutch releases and it revolves
freely on its shaft. Once the
stator becomes inactive, there is
no further multiplication of engine
torque within the converter. At
this point, the converter is mere-
ly acting as a fluid coupling as
both the converter pump and tur-
bine are being driven at approxi-
mately the same speed - or at a
one-to-one ratio.
A hydraulic system pressurized
by a gear type pump provides the
working pressure required to op-
erate the friction elements and
automatic controls.
External control connections to
transmission are:
Manual Linkage - To select the
desired operating range.
Engine Vacuum - To operate a
vacuum modulator unit.
12 Volt Electrical Signal - To
operate an electrical detent sole-
noid and stator solenoid.
A vacuum modulator is used to
automatically sense any change
in the torque input to the trans-
mission. The vacuum modulator
transmits this signal to the pres-
sure regulator, which controls
line pressure, so that all torque
requirements of the transmission
are met and smooth shifts are
obtained at all throttle openings.
The detent solenoid is activated
by an electric switch on the car-
buretor. When the throttle is fully
open, the switch on the carburetor
is closed, activating the detent
solenoid and causing the trans-
mission to downshift at speeds
below approximately 70 MPH.
The stator control solenoid is
activated by a signal from a
switch on the carburetor linkage
at engine idle which changes the
stator blade angle from low to
high. It is also energized at 48°
and over of carburetor opening
by a switch on the carburetor
linkage to change the stator
blades from low angle to high
angle.