T
ransmission
9803/3280
Issue
1
27
-
3
27
-
3
Systems
Description
Section
F
Section
F
Synchro Shuttle Gearbox
2/4 Wheel Drive Clutch Operation
- Spring ON/Pressure OFF Type
4 Wheel Drive Operation
This clutch is of the ‘Spring-ON (4WD)/Pressure-
OFF (2WD)’ type. The clutch is engaged and
disengaged by introducing or dumping pressurised
oil behind piston
C
via a solenoid valve
A
. The
solenoid valve is operated by a switch in the cab.
When the switch is in the 4 wheel drive position,
solenoid valve
A
is de-energised. With the solenoid
A1
de-energised, the valve spool moves under the
force of the spring
A2
. The oil supply to the piston
C
is blocked, (shown at port
3
). At the same time oil
vents from the back of piston
C
to the sump via
ports
1
and
2
.
Because there is no pressure behind piston
C
, the
clutch friction/counter plates of clutch pack
B
are
forced together by disc springs
D
, thus driving the
output yoke
E
.
A406220