Removing and install the GPA40 PTO clutch


To remove the rear PTO clutch, the tractor must be separated between the gearbox and the rear axle.


Disconnect the tractor between the gearbox and the rear axle.
Remove the right-hand hydraulic cover plate.
Remove the 17-bar hydraulic pipe (GTA1040 tractor transmission) or 21-bar hydraulic pipe (GTA1540 tractor transmission). This pipe is located at the top right of the mating face of the right-hand hydraulic cover plate on the centre housing. It links the clutch and the right-hand hydraulic cover plate.


Remove:
- the union and the transfer pipe, which are fitted above the centre housing and are used to lubricate the clutch;
- the sensor (1) (GTA1040 tractor transmission);
- the sensors (1) and (2) (GTA1540 tractor transmission). The sensor (1) (output speed) and sensor (2) (input speed) are located above the centre housing. They inform the tractor's electronic system of the clutch behaviour.



Removal 
Unscrew the four M12 V screws. These screws fix the support (32) of the rear PTO clutch to the
centre housing.
Using a suitable tool and the original PTO shaft, remove the clutch complete with support (32) from
the centre housing. The support (32) is positioned on the centre housing via two pins P. Remove:
- the sealing ring (3);
- the circlip (1).
Separate the support (32) from the rear PTO clutch.

Reinstall
Check the bore of the ring (4) for correct surface condition. If the diagnosis is inconclusive, replace
the defective part(s). Check that the seal rings (5) do not show any of the following:
- hardness;
- chipping;
- cuts.
Damage to the rings, even if it is minor, risks causing a leak followed by a drop in pressure, which could disrupt the operation of the clutch. If removed, using a press and a suitable fixture, Install and position the ring (4) at a distance of 0.50 mm.
This distance is measured between mating face F of the bearing on the support (32) and the end of the ring (4).
Check that the hydraulic ports are not obstructed.


Test Install the seal rings (5), new or reused, into the grooves of the shaft of the clutch unit (9). Check that the seal rings turn freely in their grooves.
After this check:
- remove the seal rings and lightly smear with miscible grease;
- definitively reinstall the seal rings;
- check that the ends of the seal rings do not protrude beyond the rim of the shaft of the clutch unit (9). Slide the support (32) onto the rear PTO clutch.
Install the circlip (1) on the shaft of the clutch unit (9). Check that the circlip is correctly at the base of the groove. Check that the PTO clutch is not obstructed against its support (32) by ensuring there is a slight clearance between the support and the clutch. Reinstall the sealing ring (3) located at the end of the shaft of the clutch unit (9).
Check that the pins (P) are present. Install the clutch and its support (32).
Install and tighten screws V to 100-130 Nm.

Reinstall:
- the transfer pipe and union used to lubricate the clutch;
- the 17-bar hydraulic pipe (GTA1040 tractor transmission) or 21-bar hydraulic pipe (GTA1540 tractor transmission) located between the clutch and the right-hand hydraulic cover plate. Install the sensor(s) by proceeding as follows:

GTA1040 transmission
- Lightly smear the sensor thread (1) with Loctite FORM A Gasket 2 or equivalent.
- Tighten home the sensor, without forcing, until its end is positioned against the drive hub (21).
- Unscrew the sensor by three quarters of a turn.
- Moderately tighten the nut.


GTA1540 transmission 
- Lightly smear the sensor thread (1) with Loctite FORM A Gasket 2 or equivalent.
- Tighten home the sensor, without forcing, until its end is positioned against the drive hub (21).
- Unscrew the sensor by three quarters of a turn.
- Moderately tighten the nut.
- Lightly smear the sensor thread (2) with Loctite FORM A Gasket 2 or equivalent.
- Tighten home the sensor, without forcing, until its end is positioned against the clutch unit (9).
- Unscrew the sensor by three quarters of a turn.
- Moderately tighten the nut.

Reinstall the right-hand hydraulic cover plate. Manually check the backlash between the gear (28) and the hydraulic-pump-driven gears (Load Sensing 110 l/min hydraulic equipment).
Reconnect the tractor between the gearbox and the rear axle.
Start the engine. Check:
- the operation of the clutch and all hydraulic components;
- the tightness of the systems.