T
ra
n
s
m
is
s
ion
9803/
3280
Issue
1
Syncro Shuttle Gearbox
Forward/Reverse Clutch Operation
The forward/reverse clutch unit
1
transfers drive from the
input shaft
A3
to either gear
G1
or gear
G2
depending on
which of the two clutches (
A1
or
A2
) is engaged, giving
forward or reverse drive. When neither clutch is engaged,
neutral is selected.
The clutches are of the wet, multi-plate type.
The c lut c h housings and inp ut shaft are a one p iec e
assembly
A3
. The assembly is permanently driven by the
engine via the torque converter. Clutch counter plates
3
are
also permanenty driven via meshing teeth inside the clutch
housings.
Clutch friction plates
4
are meshed with the gear/plate
carriers (
G1
and
G2
).
In the diagram, clutch
A1
is engaged. The counter plates
3
and friction plates
4
are pressed together by hydraulically
actuated piston
5
. Drive is then transmitted from the input
shaft to the gear
G1
.
Clutch
A2
is disengaged and no drive is transmitted to
gear/plate carrier
G2
. The gear is also free to rotate on the
input shaft assembly.
Actuation of the hydraulic pistons
10
and
5
is controlled via
three position solenoid valve
E
†.
When neut ral is selec t ed , so leno id s
E1
and
E2
are
deactivated and the flow of pressurised oil to the clutches is
blocked. Springs
8
and
9
move the pistons away from the
clutch plates and oil from both pistons is vented to the
sump.
When either forward or reverse is selected, the solenoid
valve
E
diverts pressurised oil via cross drillings inside the
input shaft
A3
to the appropriate clutch (piston
10
or
5
) in
the unit. Pressure from the other clutch is vented to the
sump via the solenoid valve spool. Oil is prevented from
leaking by seals
6
on the pistons and ring seals
7
on the
input shaft
A3
.
† The valve
E
is shown using symbols. For an explanation of
how the symbols work, see
Section E
,
Introduction to
Hydraulic Schematic Symbols
.
26 -
1
26 -
1
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