GPA30 rear PTO - Shiftable output shaft


The GPA30 rear axle PTO housing encloses:
- the driving pinions;
- the driven pinions (7) (18) (540/1000 rpm or, optionally, 750/1000 rpm);
- the shiftable output shaft (13);
- a coupler (10) controlled by a fork (31).


The shiftable output shaft is supported:
- at the front by a cylindrical roller bearing (24). This bearing is directly fitted onto the rear partition of the centre housing;
- at the rear, by two taper roller bearings (3) (19) and (8) (21).
Taper roller bearing clearance is adjusted using shim(s) (23) placed between the PTO housing and the rear bearing (22). The driven pinions (7) (18) are constantly meshed with the upper shaftline driving pinions (see chapter 7). The hub (11) of the coupler is splined to the shiftable output shaft (13).
The driven pinions (7) (18) drive the shaft when coupler (10) is moved either forwards (540 or 750 rpm), or rearwards (1000 rpm). When one of the pinions (7) (18) transmits movement to the shiftable output shaft (13), the other pinion is passive and idles on its shaft. A fork (31) fitted on the pin (28) allows selection of the required speed (540 750 - or 1000 rpm). This fork may be controlled either by an external lever located on the right-hand side of the PTO housing, or via a cable operated by a lever placed inside the cab. The castellated washer (4) is integral with the shiftable output shaft (13) via a tab. This washer informs the tractor electronic system of the output speed of the shiftable shaft via a sensor (if fitted) located on the lower right-hand side of the PTO housing.

Lubrication
A central channel with radial ports on the shiftable output shaft (13) provides splash lubrication of:
- the driven pinions (7) (18);
- the front cylindrical roller bearing (24);
- the rear taper roller bearings (3) (19) and (8) (21).
The oil tightness of the rear bearing is provided by cassette seal (14) and O'ring (15).

Parts list 
(1) Circlip (2) Screw (3) Bearing cone (4) Castellated washer for sensor (if fitted) (5) Flange shaft (6) Screw (7) 540 or 750 rpm driven pinion (8) Bearing cone (9) Protector (10) Coupler (11) Hub (12) Circlip (13) Shiftable output shaft (14) Cassette seal (15) O’ring (16) Circlip (17) Circlip
(18) 1000 rpm driven pinion (19) Bearing cup (20) Splined washer (21) Bearing cup (22) Rear bearing (23) Shim(s) (24) Cylindrical roller bearing (25) Oil deflector (26) Circlip (27) O’ring (28) Pin (29) Pads (30) Set screw (31) Fork (33) Internal or external (depending on version) control link (34) Screw
(35) Locating pin (36) Cup cap

Legend
A External PTO control
B Internal PTO control



Removing - refitting the 540/1000 rpm or 750/1000 rpm driven pinions and control fork

Split the rear PTO housing from the centre housing.

Removal 
Place the PTO housing flat on a workbench.
Remove the block consisting of the PTO clutch (15) and unit/driving pinions (23) assemblies while simultaneously removing the driven pinion (7).
Remove the link (33). Undo the set screw (30).


Take out the PTO housing:
- the pin (28). Discard the O'ring (27);
- the fork (31) with its pads (29).
Take off:
- the circlip (26);
- the coupler (10);
- the hub (11);
- the circlip (1);
- the driven pinion (18).


Refitting 
Clean and check all components. Replace any defective parts. Check that the central channel and radial ports of the shiftable output shaft (13) are not obstructed; Lubricate the friction ring (1) of the driven pinion (18).


Refit:
- the driven pinion (18);
- a new circlip (1);
- the hub (11);
- the coupler (10);
- a new circlip (26).
Refit in the PTO housing:
- the fork (31) with its pads (29), lightly smeared with miscible grease;.
- the pin (28) with a new O'ring (27).
Position the fork on the pin (28). Lightly smear the thread of the set screw (30) with Loctite 242 or equivalent. Moderately tighten this screw.
Refit the link (33). Moderately tighten the screws (34).
Lubricate the friction ring (1) of the driven pinion (7).
Refit the block consisting of the PTO clutch (15) and unit/driving pinions (23) assemblies while simultaneously refitting the driven pinion (7). Fit the PTO housing in a vertical position. Assemble the rear PTO housing to the centre housing.

Removing - refitting the front bearing

Split the rear PTO housing from the centre housing.

Removal 
Note the orientation of the cylindrical roller bearing (24) in the centre housing. Extract this bearing. Extract the bearing. Remove the oil deflector (25).


Refitting
Clean and check all components. Replace any defective parts.
Refit the oil deflector in the bore of the centre housing. Using a suitable locally made fitting drift, fit the cylindrical roller bearings in the centre housing, turning the rounded profile of its metallic cage towards the shiftable output shaft (13). Manually check that the bearing is resting against the deflector. Assemble the rear PTO housing to the centre housing.

Removing - refitting the rear bearings and shiftable output shaft

Split the rear PTO housing from the centre housing.

Removal 
Place the PTO housing flat on a workbench in order to allow removal of the shiftable output shaft (13).


If fitted, remove the sensor located on the lower right-hand side of the power take-off housing. Remove the 540/1000 rpm or, optionally, 750/1000 rpm driven pinions (7) (18); Loosen the screws (2).


Remove the rear bearing (22)/output shaft (13) assembly which consists of:
- the cassette seal (14);
- the O’ring (15);
- the shim(s) (23);
- the cup (21);
- bearing cones (3) (8);
- castellated washer (4);
- circlips (16) (17).
Remove the cup (19) from the rear PTO housing.
Remove from the shiftable output shaft (13):
- the circlip (17);
- the bearing cone (3);
- the castellated washer (4);
- the bearing cone (8);
- the bearing cup (21);
- the circlip (16).
Strip the output shaft (13), removing:
- the bearing (22) with its cassette seal (14 ) and O’ring (15);
- the flange shaft (5) (if necessary).

Refitting
Clean and check all components. Replace any defective parts. Check that the central channel and radial ports of the shiftable output shaft (13) are not obstructed;
Equip the output shaft (13) by refitting:
- the flange shaft (5). Tighten the screws (2) to torque;
- the rear bearing (22). If necessary, replace the cassette seal (14) and O’ring (15).
On the shiftable output shaft, refit:
- the circlip (16);
- the bearing cup (21);
- the bearing cone (8);
- the castellated washer (4);
- the bearing cone (3);
- the circlip (17).
Refit the cup (19) in the rear PTO housing.
Refit the original shim(s) (23) onto the bearing block (22) only if the rear bearings do not need shimming. The rear bearings must be shimmed if at least one of the following parts needs replacing:
- PTO housing;
- castellated washer (4);
- bearing cones and cups (3)(8) and (19)(21);
- rear bearing (22).
Refit the rear bearing (22)/shiftable output shaft assembly on the PTO housing. Lightly smear the thread of the screws (2) with Loctite 242 or equivalent. Tighten these screws to a torque of 72 - 96 Nm.
Refit the driven pinions (18) (7):
If necessary, refit the sensor located on the lower right-hand side of the power take-off housing. Moderately tighten the screw. Fit the PTO housing in a vertical position. Assemble the rear PTO housing to the centre housing.