Buick LeSabre 1965 Service Manual page 231

SUPER TURBINE "300'
HYDRAULIC CONTROLS 5 - 1 7
SECTION 5-B
HYDRAULIC CONTROLS
CONTENTS OF SECTION 5-B
Paragraph
5-5
Subject
Page
Oil Pump and Pressure
Regulator 5-17
5-6 Hydraulic Controls 5-18
Paragraph
5-7
Subject
Transmission Assembly Removal
and Installation
5-8 Adjustments on Car
Page
5-30
5-31
5 - 5 OIL PUMP AND
PRESSURE
REGULATOR
a. Oil Pumps
A positive displacement internal-
external gear type oil pump is
used to supply oil to fill the con-
verter, for engagement of t h e
forward and reverse clutches for
application and release of the low
band and to accumulate oil for
lubrication and heat transfer.
b. Main Pressure Regulator
Valve
The pressure regulator valve lo-
cated in the pump cover is used
as the basic control of hydraulic
pressure within the transmission.
1. First Stage Regulation
When the engine is idling or has
EX.
M A I N PRESSURE
REGULATOR VALVE
just been started, oil enters the
main pressure regulator valve
assembly between the first and
second lands and flows through
interconnecting drilled holes in
the valve to occupy the space
between the third land and the oil
pump cover. Oil under pressure
between the third land and the
pump cover moves the valve
against its spring to uncover the
port which directs oil to the con-
verter and thence to the oil cooler
and lubrication systems of the
transmission. Figure 5-14 shows
the pressure regulator valve in
first stage regulator position.
2. Second Stage Regulation
As higher engine speeds are at-
tained, the volume of oil leaving
the pump increases until the valve
moves to the position shown in
Figure 5-15 which opens a port
to allow main line oil to escape
REV.
MOD.
*7
If
U I ) I
EX.
MAIN PRESSURE
REGULATOR VALVE
J \
Figure 5-14—Pressure Regulator Valve
(First Stage Regulation)
Figure 5-15—Pressure Regulator Valve
(Second Stage Regulation)
to suction to regulate pressure.
Second state regulation is only
necessary d u r i n g operation at
high speeds or operations with
cold oil.
3. Boost Valve
A boost valve at the spring end of
the pressure regulator v a l v e
functions to raise line pressure
when necessary by adding hydrau-
lic pressure to the spring pres-
sure on the main p r e s s u r e
regulator valve.
4. Modulator Boost
With the m a n u a l shift control
valve positioned in drive range,
oil under pressure varied by op-
erating c o n d i t i o n s (load, car
speed, grade, etc.) is directed to
the space between the first land
of the boost valve and the valve
body. Oil under pressure in this
space has the same effect as in-
creasing the s p r i n g pressure
against the pressure regulator
valve, that is, it increases main
line oil pressure.
5. Reverse Boost
With the m a n u a l shift control
valve positioned in reverse range,
oil under pressure is directed to
the space between the first and
second lands of the boost valve.
Since the second land is larger
than the first, the boost valve
bears on the spring end of the
pressure regulator valve adding