Buick LeSabre 1965 Service Manual page 237

SUPER TURBINE "300'
HYDRAULIC CONTROLS 5 - 2 3
valve. Modulator pressure applies
a force to the space between the
first land of the boost valve and
the oil pump body causing it to
move to the right in Figure 5-32.
As the boost valve moves to the
r i g h t it contacts the pressure
regulator v a l v e . This hydraulic
force combined with n o r m a l
spring force on the pressure reg-
ulator valve results in higher
main line pressure. Also modu-
lator pressure is routed through
the detent valve and modulator
limit valve to the shift control
valve.
When sufficient car speed has
been obtained, the governor valve
will move allowing drive oil to be
directed at regulated pressure to
the space between the first land
of the shift valve and the valve
body and between second and third
lands of the modulator valve, be-
tween the second and third lands
of the modulator limit valve and
in the space between the first
land of the high speed down shift
timing valve and the valve body.
As governor pressure is received
b e t w e e n the second and third
lands of the modulator valve it
will t e n d to move the v a l v e
a g a i n s t i t s spring, r e d u c i n g
modulator pressure.
When governor pressure reaches
a high enough value the shift valve
will move to the right allowing
drive oil to apply the forward
clutch and release the low band.
k. Operation of Hydraulic
Controls in Drive Range
(Full Throttle to Detent
Switch Pitch Only)
During operation in Drive range
at full throttle to detent switch
pitch only, the stator control
solenoid is energized. See Figure
5-33.
Main line oil passes through the
pressure regulator valve to the
converter and stator c o n t r o l
valve. Energization of the stator
control solenoid allows oil from
the center of the valve to flow to
exhaust. Converter oil pressure
against the valve body and the
first land of the valve moves the
valve against its spring until it
bottoms in its bore. When the
valve reaches the bottom of its
bore it will exhaust the stator,
switching the blades to high angle.
Main line oil entering the manual
shift control valve is routed into
the drive oil p a s s a g e and then
directed to the governor valve,
shift valve, detent valve, high
speed down shift timing valve and
low servo. Main line oil directed
to the modulator valve enters be-
tween the first and second lands.
At low engine vacuum, the vacuum
modulator tends to keep the valve
toward the bottom of its bore. In
this position, oil is d e l i v e r e d
through a drilled passage in the
valve to the space between the
first land of the valve and the
valve body. Oil pressure in this
area plus governor pressure on
the second land of the second
modulator valve will tend to move
the valve against the force of its
spring to regulate modulator oil
pressure leaving the valve. At the
same time, line oil pressure
enters the area between the first
and second lands of the modula-
tor valve and into the modulator
pressure l i n e . Modulator o i l
leaves the modulator valve and
is routed to the boost valve, de-
tent valve, modulator limit valve,
and to the shift control valve.
Modulator pressure a p p l i e s a
force to the space between the
first land of the boost valve and
the oil pump body causing it to
move to the right in Figure 5-33.
As the boost valve moves to the
right it contacts the pressure
regulator valve. This hydraulic
f o r c e combined w i t h normal
spring force on the pressure reg-
ulator valve results in a higher
main line pressure. Also limited
modulator pressure is r o u t e d
through the detent valve and to the
modulator limit valve. Limited
modulator from t h e modulator
limit valve is routed to the shift
control valve.
When sufficient speed is obtained,
the governor valve will move,
allowing drive oil to be directed
at reduced pressure to left end of
the shift valve and between the
second and third lands of the
modulator v a l v e , between the
second and third lands of the
modulator limit valve and at the
left end of the high speed down
shift timing valve. As governor
pressure is received between the
second and third lands of the
modulator valve it will tend to
move the valve to the right, re-
ducing modulator pressure. When
governor pressure reaches a high
enough value, the shift valve will
move to the right allowing drive
oil to apply the forward clutch.
I. Operation of Hydraulic.
Controls in Drive Range
(Full Throttle Detent and
Switch Pitch)
During operation in Drive range
at full throttle detent and switch
pitch, both the stator control
valve and detent valve solenoids
are energized. The manual shift
control valve is positioned as
shown in Figure 5-34.
Main line oil passes through the
pressure regulator valve to the
converter and detent valve. When
the stator control valve solenoid
is energized it allows oil from the
center of the valve to flow to
exhaust. Converter oil applying
force to the area between the
valve body and the first land of
the valve moves the valve against
its spring pressure to the bottom
of its bore.
When the valve reaches the bot-
tom of its bore it will exhaust the
stator, switching the pitch to high
angle. Converter pressure o i l
applies force to the area between
the valve body and the first land