Removing and install the Park Lock unit


Remove the components restricting access to the Park Lock unit.


Disconnect the connectors (TR5) to (TR8) connected to the switches (18) and (19) and the solenoid valves (21) and (22), marking them beforehand.
Disconnect the 17 or 21 bar supply pipe connected to the union (23).
Manually disengage the Park Lock.

Removal
Remove the M12 screws (27) and the nut (29) (if fitted) but not the M10 screws (15).
Separate and remove the Park Lock from the centre housing.
Recover the push rod (10) without allowing it to fall inside the centre housing.

Install
Clean the mating face of the Park Lock on the centre housing and on the unit (7).
Smear the bottom end of the push rod (10) with Molykote type grease or equivalent. Reinstall this rod into it compartment on the actuator lever (8).
Replace the two "O" rings providing the seal between the Park Lock unit (7) and the centre housing.
Smear the housing of the piston (2) with Molykote type grease or equivalent. Position and refit the Park Lock, fitting the upper end of the push rod (10) into the compartment on the piston (2). Lightly smear the thread of the screws (27) and the thread of the nut (29) (if fitted) with Loctite 542 or equivalent. The thread of the screws and the stud (28) (if removed) must be smeared with Loctite as their ends protrude inside the centre housing. Tighten the screws (27) and the nut (29) to 100 to 130 Nm.

Reinstall the components which were taken off for hindering the removal of the Park Lock unit.
Restore the original functions to the Park Lock (disengagement and engagement) by completely unscrewing the special screw (5).
Reconnect the 17 or 21 bar supply pipe connected to the union (23).
Reconnect the connectors (TR5) to (TR8) to the switches (18) and (19) and the solenoid valves (21) and (22). Start the tractor engine.


Slowly move the tractor several meters over a track with a slight slope and immediately place the shuttle lever back in the neutral position. Before stopping the tractor, push the pushbutton to engage the Park-Lock and carry out an initial test.
When engaging the Park Lock, check that the tractor is immobilized by noting a slight hesitation caused by the transmission locking.
Repeat the above procedure several times to confirm that the Park Lock is operating correctly.
While seated in the operator's seat, move the tractor onto a track with a steeper slope. Stop the engine and check:
- the efficiency of the Park Lock
- that the hand brake is operating correctly
Check that there are no leaks in the hydraulic system (union, mating face, switches and solenoid valves).

Disassembling and reassembling the Park Lock unit


Remove the Park Lock comprising the unit (7) and the cover plate (20).
Unscrew and remove:
- the solenoid valves (21) and (22)
- the switches (18) and (19) fitted with their seal.


These switches are located on the cover plate (20) and on the unit (7) respectively. Recover the pushrod (11). The pushrod (11) acts as a transmission component between the switch (19) and the piston (2).

Disassembly
Completely unscrew the special screw (5) so that the Park Lock is in the manual and as a result, the Belleville washers (14) are almost released.
Unscrew the screws (17). Release and remove the cover plate (16).
Remove the circlip (25) and the pin (3).


Place the Park Lock in a press, protecting the underside of the unit (7) using two pieces of flexible protection (P). Also slide a flexible protection (P) over the cover plate (20).
Apply the hydraulic press ram to the flexible protection (P) without exerting any force (F) on the cover plate (20). Unscrew the screws (15). Slowly decompress the hydraulic press ram to decompress the Belleville washers (14). Remove:
- the cover plate (20)
- the Belleville washers (14), first noting their number and positioning The eight Belleville washers are referenced in the spare parts catalogue in the form of a kit.


On the cover plate (20):
- Drive out the spring pins (24)
- Completely unscrew the special screw (5)
- Recover the wedge (4)
- Remove the "O" ring (6) and discard it


Take out the piston (2) from the Park Lock unit (7).
Remove and discard the "O" rings (12) (13).

Reassembly
Clean:
- the mating faces of the Park Lock unit (7)
- all parts.
Using a jet of compressed air or a flexible iron wire, check that the hydraulic channels of the Park Lock unit (7) are not blocked.
Check:
- that the pushrod (11) for the switch (19) moves freely in its housing
- that there is a rivet fitted to the outer end of each hydraulic channel of the Park Lock unit (7)
Temporarily remove the seals (12) and (13) from the piston (2). Test fit the latter inside the Park Lock unit (7). Check that the piston moves freely inside its bore with no "hard" points.
Eliminate any impurities that may have become accidentally lodged inside the chamber of the piston (2).
Lubricate the seals (12) and (13) with clean transmission oil. Install these seals into the grooves of the Park Lock unit (7).


Hold the piston (2) above the Park Lock unit (7), positioning its flat section so that it is facing towards the return port.


Install the piston (2), gently tapping its centre in a circular motion using a plastic hammer. After fitting, check that there are no fragments of seal around the piston.
Lightly smear the upper mating face of the Park-Lock unit with Loctite 5206 or equivalentReinstall the Belleville washers (14).


Install and position the cover plate (20) on the Park Lock unit (7). Test fit to check that the wedge (4) is correctly aligned with the clevis of the piston (2). If the alignment is incorrect, correct it.


Place the ParkLock in a press, using the same protections that were used for removal.
Using the ram press, exert a moderate force (F) on the cover plate (20) so as to compress the Belleville washers. As soon as the cover plate (20) reaches the ParkLock unit (7), screw on and tighten the two screws (15) to 57-77 Nm.


Lubricate the "O" ring (6). Install it into the groove of the cover plate (20).
On the cover plate (20), screw on the special screw (5) and fit the wedge (4) at the same time. Form a wedge/special screw assembly using two new spring pins. Lightly smear the upper mating face of the cover plate (20) with Loctite 5206 or equivalentReinstall the cover plate (16). Tighten the screws (17) to a torque of 12 to 16 Nm.

Ensure that each switch is fitted with a new seal.


Install:
- the switch (18) onto the cover plate (20)
- the pushrod (11) and the switch (19) to the ParkLock unit (7).
Tighten the switches to a torque of 15 - 25 Nm.
Install the solenoid valves (21) (22) in the same positions as before disassembly.
Tighten the following onto the solenoid valve (22):
- the spool to a torque of 18 – 20 Nm.
- the solenoid to a torque of 4 -5 Nm.