N
D
R
2
1
PUSH-BUTTON UNIT
MANUAL SELECTOR
VALVE
R
N
SECONDARY
REACTION
AREA
SELECTOR
D
SPRING
LEVER
L
STOP
PRIMARY REACTION AREA
REGULATOR
VALVE
ASf02067
FROM OIL PUMP
VENT
Figure 2-67.--Oil regulator.
the vehicle speed. There are two types of governors in
uncovers a vent port that bypasses oil back to the
general use--the centrifugally operated spool valve
suction side of the pump or the sump. The valve seeks
and the fluid velocity type. Figure 2-68 shows both a
and stabilizes at a pressure that balances the setting of
fluid velocity and a centrifugally operated governor.
the spring. The oil that is delivered to the control
system by the regulator valve is known as the line or
The centrifugal governor usually consists of a
main line pressure.
weight and valve assembly enclosed within the
governor housing. The spool valve is free to move
Manual Selector Valve
inside the cylinder or bore of the housing within the
The oil pump (or pumps) and pressure regulator
REGULATED
provide the hydraulic system with the fluid and
OIL PRESSURE
OUTPUT SHAFT
pressure necessary to operate the transmission
operating units. However, to control the transmission,
a valve controlled by the operator is required. This
operator-controlled valve is commonly called the
"manual valve." The manual valve can be positioned
by the operator to provide low-gear ratios, or low- and
VENT
WEIGHT AND
SPRING
high-gear ratios, reverse, and neutral; on some
ASSEMBLY
MAIN LINE
OIL PRESSURE
transmissions an intermediate range of ratios can be
selected as well as park. The operator may use a
selector lever or a push button to control the valve (fig.
A. CENTRIFUGAL GOVERNOR
2-67).
PITOT TUBE
The manual valve acts as a directional control
DRUM CAN
valve. It blocks fluid flow and pressure to the operating
units while in the neutral position; in other positions, it
directs oil to one or more of the operating units.
OUTPUT SHAFT
Governor
VANES
A governor is normally mounted on the output
shaft of the transmission, rotating with it; therefore, it
B. FLUID VELOCITY GOVERNOR
ASf02068
is sensitive to the speed of the vehicle. Because the
governor is sensitive to the speed of the vehicle, it is
Figure 2-68.--Centrifugal and fluid velocity
used to transmit fluid under pressure, proportional to
governors.
2-52