clutches and brake bands. The hydraulic pressure that
to produce the required gear ratios.
actuates these locking devices is controlled by the valve
body. The valve body can be thought of as a hydraulic
23-4. Operator Controls. The only operator control
computer that receives signals that indicate vehicle
for an automatic transmission is the gearshift lever
speed, throttle position, and gearshift lever position.
although the accelerator pedal also can be considered
Based on this information, the valve body sends
an operator control because it forces the transmission to
hydraulic pressure to the correct locking devices
shift to a lower ratio when it is fully depressed
Section II. DRIVE TRAIN MECHIANISMS
b. Construction (Fig. 23-2). The multiple-disk
23-5. Multiple-Disk Clutch.
clutch is comprised of the following components:
a. General (Fig. 23-2). The multiple-disk
(1) Disks and Plates. The active
clutch, in most cases, is used to transmit torque by
components of the multiple-disk clutch are the disks and
locking elements of the planetary gearsets to rotating
the plates. The disks are made of steel and are faced
members within the transmission. in some cases, the
with a friction material. They usually have teeth cut into
multiple-disk clutch also is used to lock a planetary
their inner circumference to positively key them to the
gearset element to the transmission case so that it can
clutch hub. The plates are
act as a reactionary member.
Figure 23-2. Multiple-Disk Clutch.