Selector cover


Tractors with a mechanical reverse shuttle are equipped with either a cab or a platform and a selector cover of similar construction. For the version with the footstep. The selector cover, installed on the right-hand side of the housing on the Heavy gearbox, has two separate levers providing two different functions:
- front lever - for controlling the reverse shuttle,
- rear lever - for selecting the four basic speeds and the two Hare / Tortoise ratios (Hi - Lo).

2

Tractors with cab
- Control lever (1) (Fig.3) mounted on the left-hand part of the instrument panel fascia actuates the reverse shuttle via a control cable.
- Control lever (2) (Fig.3) located above and to the right of the console selects the four basic speeds and also acts on the Hare/Tortoise function, via a rod and cable.

Special point
When the tractor is stopped, cell “C” mounted on a bracket on the selector cover (Fig.3) informs the user that a gear has remained engaged, and that the handbrake is on. The warning is issued by a buzzer located under the instrument panel surround.

1

Parts list
(1) Return ports (2) Grounding lug (3) Screw (4) Temperature probe with seal. (5) Seal (6) Shouldered ring (7) Selector cover (8) Finger-pin assembly (reverse shuttle) (9) Finger-pin assembly (speeds) (10) Grid (11) Screw (12) Spring (13) Spring cup (14) Spring cup (15) Spring (16) Spring cup (17) Seal
(18) Shouldered ring (19) Seal(s) (20) Hare / Tortoise switch

3

Reverse / Forward lever
On tractors with cabs, lever (1) (Fig.3) has the following positions:
- upwards (forward drive)
- downwards (reverse drive)
Moving lever (1) (Fig.3) results in rotation of the pin which is hard-mounted to finger (8); the follower moves selector “S” (Fig.1).

Gear lever
Selecting 1st / 2nd gear
- Gear lever (2) pushes lever “L” (Fig.3) and engages finger (9) in the 1st / 2nd gear selector fork (Fig.1).
- The first ratio is obtained by moving lever “L” upwards, and the second ratio by moving it downwards.
Selecting 3rd / 4th gear
- In this configuration, gear lever (2) (Fig.3) is in the intermediate position; finger (9) integral with shaft “A” is engaged in the 3rd / 4th gear selector fork (Fig.1).
- The third ratio is obtained by moving lever “L” upwards, and the fourth ratio by moving it downwards.

Safety interlock
- A locking system located on the rear face of the gearbox, on the end of the selector rails, prohibits accidental gear shifting.

Hare / Tortoise function
Identification of components (Fig.4)

4

(1) Solenoid valve (2) O’ring (3) Piston (4) Bearing (5) O’rings (6) Circlip (7) Selector cover

Selecting the Hare / Tortoise range is done with the gear lever in the neutral position, by pulling lever "L" towards the outside of cover (Fig. 3). Finger (9) presses the end of switch (20) (Fig. 1) which informs the electronic system that the Hare / Tortoise solenoid valve can be switched.

Hare position (Fig.4)
Solenoid valve (1) mounted on selector cover (7) is closed, which causes a pressure drop in chamber "B".
The constant pressure (17 bar) in chamber "A" is applied to the annular face of piston (3), which moves forward and entrains fork "F1" towards the Hare position under the action of selector "S". The oil contained in chamber "B" returns to the sump via the solenoid valve.

Tortoise position (Fig.4)
Moving switch (20) (Fig. 1) again causes opening of solenoid valve (1) (Fig.4). Oil pressurised at 17 bar arrives in chamber "B". Since the pressure acting on the large diameter of the piston is greater than that acting on the annular face, it forces the piston to retract, driving selector "S" and fork "F1" towards the Tortoise position. The oil contained in chamber "A" returns to the 17 bar circuit.

Removing and refitting the cover


Immobilise the tractor. Chock the left rear wheel. Set the handbrake.
Place chocks between the frame and the front axle.
Remove the right rear wheel or set to wide tread. Install an axle stand if necessary.
Pivot the footstep assembly and battery chest or remove any neighbouring parts likely to impede removal of the selector cover (depending on version).
Drain the gearbox.
Disconnect the electrical harnesses on the cover.
Unscrew the tube and hose unions.

Tractors with cabs. Gear control.
Disconnect the harness from cell "C" (Fig.3). Remove ball joint (4). Remove screw (3).
Remove pins (11). Disconnect ball joint (5).
Note the adjustment of cable (6). Slightly loosen upper nut (12) and separate the cable from bracket (2). Reverse shuttle control.
Remove clips (1). Note the adjustment of cables (2). Loosen nuts (3). Separate the cables from bracket (4).
On tractors fitted with a creeper unit, disconnect control cable (1).
Remove screws (3), taking care to identify the position of grounding lug (2).
If installed, remove bracket (2) supporting the creeper control cable.
Release and remove the selector cover.
Clean the mating faces on the gearbox and cover.

Install the following parts:
On the cover: the Hare / Tortoise piston in the "Hare" position
On the gearbox: the Hare / Tortoise fork in the "Hare" position, the 1st / 2nd gear and 3rd / 4th-gear selector forks and the reverse shuttle fork in the neutral position.

Coat the mating face of the gearbox housing with sealing compound (Masterjoint 510 Loctite or equivalent).
Turn the gear and reversing control linkage on the cover to engage them in their respective selectors during positioning of the cover on the gearbox.
Install the bracket for the creeper control cable (if installed).
Position lug (2). Install screw (3) and torque to 34 - 51 Nm.
Depending on the option, reconnect and adjust the creeper gear control.
Reassemble the gear control.
Reassemble the reverse shuttle control.
Use a grease gun to grease the joints of the gear control on the selector cover.
Install any items previously removed around the cover.
Replace the wheel and torque the screws or nuts depending on the version.
Service the oil in the sumps and check the level in the sight glass located on the left-hand of the centre housing.
Remove the chocks between the frame and front axle. Release the handbrake.
With the engine running, check passage of all gears and the reverse shuttle. Also check the Hare/Tortoise position. If necessary, and with the engine stopped, adjust the controls.
Check that the buzzer of the safety cell vibrates correctly (contact set, handbrake on and gear engaged).
Carry out a road test.

Replacing the Hare/Tortoise piston seals (Fig.4) 
Remove the cover.
Remove circlip (6). Extract piston (3) with bearing (4) and scrap O’rings (2) and (5).
Clean and check the parts; replace any that are faulty.
Without installing the O’rings on the piston, check that the latter slides freely in the bore in the cover.
After inspection, lubricate and fit new O’rings.
Install the selector cover.
- Replacing piston (3), bearing (4) or circlip (6) implies checking or repeating the setting of selector "S" on the Hare/Tortoise range.

Disassembling and reassembling the selector mechanisms


Remove the cover and tighten in a soft-jaw vice.

Tractors with cabs
Remove screws (1) and (4). Remove selector (3), link rod (5) and bracket (2).
Remove the pin integral with finger (8).
Remove screw (11). Remove the gear control assembly.
Remove cup washers (14) and (16) and spring (15).
Separate the assembly comprising pin and finger (9) from grid (10). Remove spring cup (13) and spring (12).
If necessary, unscrew and remove Hare/Tortoise switch (20), the threaded fittings on return ports (1), and temperature probe (4). Recover seal(s) (19) from the Hare / Tortoise switch.
Extract seals (5) and (17).
If considered necessary to replace guide rings (6) and (18), lightly coat the edges of the replacement rings with Loctite 638 or equivalent and fit them tight so that they come into contact with the shoulders on the cover.
If removed, reinstall Hare / Tortoise switch (20) with the same number of seals as removed. Apply a light coat of Loctite 542 to the threads of the return port and the temperature probe unions, then refit the unions.

Lightly coat the outside diameter of seals (5) (17) with Loctite 542, then fit the seals tight onto cover using a suitable fixture.
From the inside of the cover, refit the pin-finger assembly (8) without damaging the lip of seal (5).
Install reversing linkage (5). Coat the threads of screw (4) with Loctite 241 or equivalent and install the screw. Torque to 30 - 35 Nm.
Reassemble spring (12) and spring cup (13) on shaft (9). Assemble the shaft with grid (10). Reassemble cup washers (14) (16), with spring (15) in between.
Install the pin-finger assembly (9) without damaging the lip of seal (17). Coat threads of screw (11) with Loctite 270 or equivalent. Install the screw and torque to 25 - 35 Nm.

Positioning bracket (2) (Fig. 10)
Install bracket (2), observing a clearance of 29 mm between the bracket and the 22-mm diameter of shaft “A” (Fig. 10). Lightly coat screw (1) with Loctite 270 or equivalent, fit the screw and torque to 25 - 35 Nm.

10

This clearance MUST be observed to ensure correct operation of the cell.
Reassemble linkage (3). Coat threads of screw (4) with Loctite 241 or equivalent, fit the screw and torque to 30 -35 Nm.
Check that the selector mechanisms move freely. Remove the cover from the vice and refit to the Gearbox.