SM02-025-0
Page 9
regulating valve is blocked at the control valve, and
direction as long as no pressure is present in that
the transmission is in neutral. Movement of the for-
specific clutch.
ward and reverse spool will direct oil, under pressure
to either the forward or reverse direction clutch as
To engage the clutch, the control valve is placed in
desired. When either directional clutch is selected,
the desired position. This allows oil under pressure to
the opposite clutch is relieved of pressure and vents
flow from the control valve, through a tube, to a
chosen clutch shaft. This shaft has a drilled pas-
back through the direction selector spool. The same
procedure is used in the speed selector.
sageway for oil under pressure to enter the shaft. Oil
pressure sealing rings are located on the clutch shaft.
The direction or speed clutch assembly consists of a
These rings direct oil under pressure to the desired
drum with internal splines and a bore to receive a
clutch. Pressure of the oil forces the piston and discs
hydraulically actuated piston. The piston is oil tight by
against the heavy back-up plate. The discs, with teeth
the use of sealing rings. A steel disc with external
on the outer diameter, clamping against discs with
splines is inserted into the drum and rests against the
teeth on the inner diameter, enables the hub and
piston. Next a friction disc with splines at the inner.
clutch shaft to be locked together and allows them to
diameter is inserted. Discs are alternated until the
drive as a unit.
required total is achieved. A heavy back-up plate is
then inserted and secured with a snap ring. A hub
There are bleed balls in the clutch piston which allow
with OD splines is inserted into the splines of discs
quick escape for oil when the pressure to the piston is
with teeth on the inner diameter. The discs and hub
released.
are free to increase in speed or rotate in the opposite
MAINTENANCE
GENERAL.
therein depends greatly on the condition and opera-
tions of the others. By studying the principles of oper-
The following General Assembly Instructions, Speci-
ation together with data in this section, it may be
fications and Service Data, and Torque Chart are
possible to correct any malfunction which may o c c u r
provided as general references to be used when ser-
in the system. Troubleshooting procedure basically
vicing any part of the transmission or the transmis-
consists of two classifications; mechanical and
sion as a whole.
hydraulic.
TROUBLESHOOTING.
Checks.
Hydraulic
The following data is presented as an aid to locating
the source of difficulty in a malfunctioning unit. It is
Before checking the torque-converter, transmission,
necessary to consider torque converter charging
and associated hydraulic system for pressures and
rate of oil flow, it is essential that the following preli-
pump, transmission, oil cooler, and connecting lines
minary checks be made.
as a complete system when checking for the source
of trouble since the proper operation of any unit
