jcb 4CX Service Manual

40 - 2 Section F Transmission 9803/3280
Section F
40 - 2
Issue 1
Fault Finding
YES
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
YES
YES
YES
NO NO
Is gearbox oil level low?
START
Is gearbox oil the correct type and
free from contamination?
Carry out a Torque Converter Stall Test
in all gears. Are all the stall speeds
outside specifications?
Carry out Mainline Oil Pressure Test
Is mainline oil pressure correct?
Carry out Mainline Oil Pressure and
Flow Tests
Is mainline oil pressure /flow correct?
Remove and dismantle gearbox.
Check condition of pump, casings for
internal/external leakage. The clutches
will have been slipping due to low oil
pressure - dismantle all clutches and
renew as required.
Check condition of pressure
maintenance
valve. Clean or renew as applicable.
Check for signs of excessive external
oil leakage.
Are all the stall speeds too low?
Top up oil level
Check the operation of the parking
and service brakes.
Check reason for contamination.
Rectify as applicable Drain and flush
oil, see Flushing the Gearbox Oil.
Carry out Torque Converter In
Pressure Test. Is torque converter in
pressure correct?
Carry out Torque Converter Out
Pressure Test. Is torque converter out
pressure correct?
It may be that another fault may have
been overlooked. Go back to the start
of the fault finding and re-check.
Cooler lines restricted or blocked. Oil
cooler blocked.
Cooler lines or cooler leaking. Internal
leakage. Remove the gearbox, torque
converter housing and pump, check
all sealing faces for damage.
Too high?
Too low?
Check condition of torque
converter relief valve.
Clean or renew as applicable.
Is the engine performance normal?
See Checking the Engine Power.
Repair the engine as applicable.
Torque converter reaction member
clutch slipping. Remove the gearbox
and renew the torque converter.
A396280
Powershift Gearbox
Chart A - Machine drives but lacks power in all gears. Gearbox oil may also be overheating.
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jcb 4CX Specifications

General

Brand	jcb
Model	4CX
Category	Compact Loader
Language	English