T
ra
n
s
m
is
s
ion
9803/
3280
Issue
1
Powershift Gearbox
Component Identification
A
Torque converter
B
Forward/input clutch assembly
C
Reverse clutch assembly
D
Mainshaft assembly
E
Layshaft assembly
F
2/4 wheel drive clutch assembly
G
Torque converter relief valve
H
Oil pressure maintenance valve
J
Transmission oil pump
K
6 speed assembly (if fitted)
L
4WD output yoke
M
Hose connection - to oil cooler
N
Hose connection - from oil cooler
P
Oil strainer
Q
Oil filter
R
Driveshaft (drives machine main hydraulic
pump)
1
Speed sensor
2
Gear drive to reverse unit clutch assembly
3
Transmission oil pressure switch
4
Steering column mounted gear selection switch
5
Solenoid control valves
6
Gearbox oil cooler
Principle of Operation
The J CB Po w ershif t is an elec t ro - hyd raulic
t ransmission unit . Gear shift ing and d irec t ion
selection are controlled using multi-disc clutch
packs.
Elec t ric ally op erat ed solenoid valves
5
d ivert
p ressurised o il (p ro vid ed b y p um p
J
) t o t he
selected clutch packs.
A combined lever/swivel switch
4
on the steering
column actuates both gear ratio and direction
solenoids.
The Powershift unit consists of a torque converter
A
, forw ard c lut c h assemb ly
B
, reverse c lut c h
assem b ly
C
, layshaft assem b ly
E
, m ainshaft
assembly
D
, 2/4 wheel drive clutch assembly
F
.
6 speed gearboxes incorporate a ‘6 speed’ shaft
and clutch assembly
K
.
The forward clutch assembly
B
is driven by the
torque converter
A
. The reverse clutch assembly
C
is permanently driven via constant meshing of spur
gears
2
. On 6 sp eed gearb oxes t he 6 sp eed
assembly is also driven via meshing gears
2
.
Driveshaft
R
is permanently driven by the engine
and runs through the hollow forward/reverse unit
shaft to the back of the gearbox. The shaft (
R
)
d rives t he g earb o x m o unt ed m ac hine m ain
hydraulic pump.
Strainer
P
and filter
Q
are used to prevent potential
system contamination by filtering dirt particles.
Gearbox oil is cooled by an air blast cooler
6
. The
cooler is part of the front mounted machine ‘cooling
pack’.
17 -
2
17 -
2
B
a
sic
O
p
e
ra
tio
n
S
e
c
tio
n F
S
e
c
tio
n F
A401330
6
4
