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Section F
126 - 2
Inspection
Before assembling the gearbox, make sure that a thorough
inspection of all components is carried out. Remember that
although a failed component may be easy to identify, the
cause of that failure may be less easy to trace. It is also
possible that a failed component may have caused damage
to other areas of the gearbox.
1
Cleaning
a
Carefully remove all traces of gasket or gasket
compound from the following components:
Note: When removing gasket compound use a gasket
*
removal product such as Loctite Chisel. Take care not to
damage the mating faces. Clean the faces with a fine
carborundum paper. Use a solvent cleaner and a clean cloth
to finally remove all traces of oil or debris.
Front and rear casing mating faces.
Front casing and torque converter housing mating
faces.
Main hydraulic pump and rear casing mating faces.
Solenoid control valve manifold and casing mating
faces.
4WD casing mating faces.
Layshaft cover and rear casing mating faces.
Pressure maintenance valve bore (front case)
b
Clean the inside of the casings using a suitable
degreasing agent.
2
General Inspection
a
Carefully inspect all gears, bearings and shafts for signs
of excessive wear or damage. If wear or damage is
evident, components must be renewed.
Note: The transfer gear shaft inner, outer bearing and
spacer assembly is a matched set. If any of the components
are damaged or worn the complete assembly must be
renewed. Components are not interchangeable between
bearing sets.
b
Make sure that all oil way cross drillings are clear and
free from debris. Blocked oil ways are a common cause
of bearing failure. If necessary use an air line to blow
through the oil ways.
3
Clutch Units
a
If clutch failure is suspected see the relevant clutch
dismantling and assembly procedure in this section.
4
Gearbox Hydraulic Pump
a
If tests have shown the pump performance to be
unacceptable, the pump must be renewed as a
complete unit.
9803/3280
Transmission
Powershift Gearbox
Purchased from www.WorkshopManuals.co.uk
b
If the existing pump is to be re-installed proceed as
follows;
Undo the security screw 4a and separate the pump
body. Carefully inspect the gear teeth, white metal
bearing and gear/body mating faces for signs of wear
and damage, (If either is evident, the pump must be
renewed).
Carefully remove and discard the oil seal 4b. Take care
not to damage the seal housing. Fit a new seal and
then re-assemble the pump.
c
Make sure that pump the mating face on the gearbox
front cover is clean and free from surface damage.
5
Oil Transfer Pipes
The front case incorporates oil transfer pipes 5a, 5b and 5c.
If the pipes are damaged or if the gearbox has been
contaminated, the pipes must be removed for cleaning or
renewal.
4x4 Gearbox: pipe 5c not fitted.
a
Using a 'crows foot' type spanner and a ratchet wrench
undo the pipes from the adaptors in the casing. Unless
pipes are being transferred to a new casing it will not
be necessary to remove the pipe adaptors.
6x4 Gearbox Only: If the adaptors are to be removed,
adaptor 5e must be removed last.
b
If the adaptors have been removed make sure that the
sealing rings are renewed and fitted correctly.
6x4 Gearbox Only: Position the lock nut 5f on adaptor
5e as shown and then fit the adaptor to the case.
Screw in until the locking nut reaches the case. Do not
tighten the locking nut down at this stage.
All Gearboxes: Fit the adaptors. Torque tighten to
70 Nm.
c
Make sure the pipes are clear and free from debris
before refitting. Loosly fit the pipes 5a and 5b. Make
sure they are fitted at the correct adaptors as shown.
6x4 Gearbox Only: Loosly fit the pipe 5c, rotate
adaptor 5e so that the pipe is not strained. Torque
tighten down the lock nut 5f to 70 Nm.
All Gearboxes: Torque tighten the pipes to 30 Nm.
6
Casings
If the gearbox casings are to be renewed, be sure to fit
blanking plugs and adapters as required. Inspect the original
casings and identify the blanking plug and adapter positions.
Transfer the plugs and adapters to the new casings. Apply
JCB Threadlocker and Sealer to the threads.
Note that new plugs may be supplied with a sealant 'patch',
in which case sealant need not be applied.
*
Note: Early gearboxes feature a '18 bolt fix' torque converter
housing. It is strongly recommended that a new '23 bolt fix'
housing and matching front case is fitted on assembly of the
gearbox. A compatible torque converter relief valve will also
be required.
Section F
126 - 2
Issue 3*
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