Power Shuttle gearbox GBA20 - Removing and install the cover plate


Immobilise the tractor. Chock the left rear wheel. Apply the hand brake. Chock between the frame and the front axle. Drain the gearbox. Raise the rear right-hand side of the tractor with a suitable jack. Remove the wheel. Place an axle stand in position. Remove the right-hand step and any surrounding parts that might hinder removal of the cover plate.


Removal 
Disconnect the harness of sensor "C". Remove the ball joint (4). Remove the screw (3). Remove the pins (11). Disconnect the ball joint (5).


Mark the adjustment of the cable (6). Slightly loosen the top nut (12) and separate the cable from the support (2).
Disconnect the control cable (1) from the creeper unit on tractors fitted with this option.


Remove the screws (3) and (4) and the nut (6), marking the location of the earthing lug (2)If fitted, remove the support (2) of the creeper unit control cableRelease and remove the selector cover plate.

Reinstall 
Clean the mating face of the gearbox and the cover plate.
Place the 3rd - 4th fork in ratio 3. Before refitting the cover plate, check that the screw (1) is present.
Lightly smear the mating face of the gearbox housing with a sealing product such as Loctite 510 or equivalent. Turn the finger (13) to the left.
Position the cover plate on the gearbox, checking that the finger is correctly fitted in the forks. Reinstall the creeper control cable support (if fitted).
Reinstall the earthing lug (2). Install and tighten the screws (3) (4) and the nut (6) to a torque of 50 - 70 Nm.
Depending on the option, reconnect and adjust the creeper control.
Reconnect the harnesses to the temperature sensor (5) and the Neutral position switch. Reconnect the transmission lever and reconnect the sensor. Perform steps in reverse order.
Using a grease gun, lubricate the joints of the gear control on the selector cover plate.


Legend 
A Indexing rod for locking the Hare/Tortoise fork L Synchronisation of the Hare/Tortoise mechanism in Hare range (3) Gear engaged (e.g. 3rd gear) (1) Screw (9) Selector cover plate (13) Finger (18) Locking stop

Check the shifting of all gears. If required, adjust the control.
As required, reinstall any components removed previously from around the cover plate. Reinstall the wheel. Tighten the nuts to a torque of 400 - 450 Nm. Top up the oil level in the housings. Check it using the gauge at the rear of the centre housing.
Remove the chocks between the frame and the front axle. Release the hand brake. Check that the buzzer of the safety sensor vibrates correctly (ignition on, hand brake on and gear engaged).
Start the engine. On the road, check the shifting up and down of the gear ratios, as well as the operation of the Hare / Tortoise range using the pulse button located on the lever.
Check the tightness of the selector cover plate mating face and of the hydraulic unions.


Disassembling and reassembling the selector mechanisms


Take off the cover plate. Secure it in a vice fitted with protective jaws.
Disassembly
Remove the screws (1). Remove the key (4) and selector (3). Separate the support (2) from the cover plate.
Remove the screws (15). Separate the cover plate (9) and support (16) comprising the gear control assembly. If necessary, extract the locating rings (17).


On the cover plate (9)
Take off the Neutral position switch (28). Recover the seal (27) and ball bearing (18).
If necessary, remove the temperature sensor (5) and the unions screwed onto the return ports (1) (10). Extract and discard the seal (25).

On the support (16)
Take off the circlip (22), washer (21) and remove the spring (20).
Release the washer (33) and toggle switch (34), marking its position and profile. Recover the plunger (31). Extract the indexing rod (35).
If necessary:
- remove the screws (19);
- remove the speed grid (14);
- extract the locating rings (17).
Reassembly 
If it was necessary to replace the guide ring (26), lightly smear its rim with Loctite 648 or equivalent. Install it up against the shoulder of the cover plate.

On the support (16)
If necessary:
- Install the locating rings (17),
- reinstall the speed grid (14) on the support (16),
- tighten the screws (19), lightly smeared with Loctite 270 or equivalent, to a torque of 29 - 37 Nm. Check that:
- the plunger (31) and indexing rod (35) move freely in the support (16),
- the flat section of the toggle switch (34) slides normally on the finger (13).
Slide the pin of the finger (13) into the support (16).
Turn the toggle switch (34) as required. Install it onto the finger (13). Fit the washer (33). Reinstall the spring (20) and washer (21). Install the circlip (22).
Slide the plunger (31) into its cavity in the support (16).
Place the finger (13) in the Neutral position. Turn the indexing rod (35) as required and fit it.

On the cover plate (9)
Check that the locating rings (17) are present.
Reinstall the gear control and support (16) assembly on the cover plate (9).
Lightly smear the thread of the screws (15) with Loctite 242 or equivalent. Tighten to a torque of 29-37 Nm.
Protect the lip of the seal (25) by surrounding the cylindrical end of the finger (13) with a flexible protection. Lightly smear the external rim of the seal with Loctite 542 or equivalent and slide it onto the protection. Remove the safety shield. Install the seal onto the cover plate using a suitable fixture.
Check that finger (13) is in the Neutral position.
Slide the ball bearing (18) into the depression on the toggle switch (34).

Checking the Neutral position switch (28)
Press manually on the button located at the end of the switch. Release the pressure and check that the button returns freely to its initial position. Repeat the operation several times. The check can be carried out using a multimeter.


Reinstall the switch complete with its seal and tighten to a torque of 15 - 25 Nm. Reinstall the support (2), allowing a distance of 29 mm between the support and the 22 mm diameter of pin A. Lightly smear the screws (1) with Loctite 270 and tighten them to a torque of 25 - 35 Nm.
This dimension must be met for the sensor to operate correctly.
Reinstall the selector (3). Install and tighten the key (4).


Checking the locking system of the indexing rod (35)
In the grid (14), move the finger (13) from 1st to 4th ratio using the selector (3) and manually check for the correct locking of the indexing rod in each of its positions. This indexing rod is linked to the Hare/Tortoise fork by an adjustable stop. If the replacement of certain components of the locking system was necessary, it is mandatory to readjust this stop.
Remove the cover plate from the vice. Reinstall it on the gearbox.

Reinstall and adjusting the gear linkage

Cab side
Preparation 
On the end of the rod (1) shaped with an angle of 166°, position the ball joint (2)Tighten the nut (3). Tighten the ball joint (4) up against the cable (6). Tighten the nut (5).


Assembly 
Place the support (7) on a workbench.
On the support, fit and tighten:
- the transmission lever
- the previously prepared rod and cable.
Reinstall and secure the support onto the right-hand wheel housing of the cab. During this operation, ensure the rod and cable are inserted through the holes in the compartments. Install the shield rings.

Selector cover plate side
Preparation 
Screw the threaded rod (9) (fitted with nuts (3) and the ball joint (4)) onto the rod (1). Tighten the ball joint (5) up against the cable (6). Tighten the nut (7).
Assembly 
Tighten and lock the other end of the ball joint (5) onto the cam (8).
On the previously fitted support (2) and lever "L", position the cam (8) and its extension block (10). Fit the pins (11), and lock them in place with new pins.
Install the ball joint (4) on the lever L. Install the washer and tighten the locknut.


Adjusting the rod (1) 
Turn the threaded rod (9) and ball joint (4) to obtain a dimension X of 17 ± 1 mm between the two nuts (3) when they are tightened.

Adjusting the cable (6) 
Adjust the sheath end to balance (as far as possible) dimensions "C" and "D". Tighten the nuts (12) without altering the adjustment.

Gear ratio and the position of the lever in the opening of the console.
This check should be performed with the gaiter of the transmission lever temporarily removed.
Engage each gear ratio. During this operation, check that the lever is never closer than 5 mm from the edge of the console.

• Lever movement is not hindered in any way by the console. Adjustment is correct. Position the gaiter.

• Lever movement is hindered by the console. The lever is positioned incorrectly. Readjust the rod (1) on the selector cover plate side in accordance with the following instructions:
- If the problem concerns the 1st or 3rd gear, reduce dimension X.
- If the problem concerns the 2nd or 4th gear, increase dimension X.
- If the problem concerns lateral movement of the lever between the 1-2 and 3-4 gear paths (Neutral position), adjust the cable sheath end (6) (dimensions C and D). Tighten the nuts (12).