Rear axle trumpets with double reduction - spacer and epicyclic reducer gears


Removing and install brake plate, crownwheels, spacer and epicyclic reducer gears 


Remove the trumpet assembly. If possible, place the trumpet in a vertical position, the input shaft (31) at the top.


Remove the bolts (40). Unstick and remove the brake plate (30).
If necessary, take off snap ring (33) and hub (32).
Disengage circlip (42) from its groove and remove the primary sun gear (44).
Disengage circlip (21), take off washer (46) and remove the input shaft (31) fitted with ball bearing race (19).
Take off circlip (45). Take out the primary planetary carrier (24). Remove the planetary gears (20).
Unstick and remove the primary crownwheel (47).
Immobilise the planetary carrier (25). Take off bolts (28). Remove holding washer (27) and shims (26).

Disengage the secondary sun gear (51). Remove the thrust washer (4).
Take out the secondary planetary carrier (25). Remove the planetary gears (18). If necessary, extract bearing (19) from the input shaft (31).
Unstick and remove the secondary crownwheel (15).
- The reason for the secondary crownwheel (15) are the large forces exerted, and its heat treatment is different compared to that of the primary crownwheel (47).
- In order to identify the crownwheels and avoid their incorrect fitting, the perimeter of the secondary


crownwheel has two diametrically opposed machined flats "M".
- This crownwheel also possesses an additional locating pin (57).
Clean the components. Replace any parts found to be defective. Remove all traces of previous sealing compound in the internal angles of the trumpet, on the crownwheels (15) (47), the spacer (48) and the brake plate (30).
- If the replacement of the oblique pipe (56) is necessary, lightly smear the end concerned with Loctite 648 or its equivalent and introduce it into the trumpet, the oblique profile turned towards bearing (12) (13).


- The bearing cup plug (55) installed at the end of the channel (see exploded view) must likewise be smeared with Loctite 542 or equivalent before insertion.

Check for the presence of the tab washer (16).
Reinstall the secondary planetary carrier (25).
Reinstall the thrust washer (4) as in the overall view. Reinstall the secondary sun gear (51) comprising ball bearing (49), washer (50) and circlip (6).
Place pin (14) and the locating pin (57) in their respective grooves located on the trumpet.
Coat the inner angle "B" of trumpet (10) with a silicone sealing compound (Silicomet type).


- The diameter of the bead (seal) must be uniform, small in section and without joins.
- This fitting information also holds true for all later sealing operations.
Position the secondary crownwheel (15), with the flats "M" along the horizontal axis of the tractor.
If necessary, reassemble the secondary planetary gears (18) with bearings (23) and stop rings (17).
Reinstall the secondary planetary gears correctly positioned on the planetary carrier (25). Install circlips (29). Place the shim(s) (26) removed during disassembly and reinstall the holding washer (27). Immobilise the planetary carrier. Smear bolts (28) with Loctite 242 and tighten them to a torque of 100 - 130 Nm.
Coat the internal angles "A" and "C" of spacer (48) with a silicone sealing compound (Silicomet type).
Position the spacer on the secondary crownwheel (15).
Place the second pin (14) in its groove in the spacer.
If necessary, reinstall the primary planetary gears (20) correctly positioned with bearings (22) on the corresponding planetary carrier. Install the circlips (29).
Position the primary crownwheel (47) on the spacer (48).
Slide the primary planetary carrier (47) onto the secondary sun gear. Turn the planetary gears to facilitate their engagement. Install circlip (45).
If disassembled, insert the ball bearing race (19) on the input shaft (31).
Engage shaft (31) installed with its bearing in the secondary sun gear (51). Place washer (46) and circlip (21).
Slide the primary sun gear (44) correctly oriented on to shaft (31). Install circlip (42).
Coat the internal angle "E" of the brake plate (30) with a silicone sealing compound (Silicomet type).
Position the brake plate on the primary crownwheel (47).
Install bolts (40) and tighten them to a torque of 90 – 120 Nm.
Slide hub (32) onto shaft (31). Using suitable pliers, fit the snap ring (33).
Reinstall the trumpet assembly.

Replacing the cassette seal

Partially drain the trumpet concerned. Chock the front wheels. Remove the rear wheel. Place an axle stand beneath the trumpet.


- Tractors are fitted with axle shaft with a diameter of 110 mm.
- Bush (1) has a larger bore and is referenced in the spare parts catalogue.
- The cassette seal (3) retains the same characteristics as that fitted to trumpets with composite drive unit.
- The bore of the bush is smeared with Loctite 648 or equivalent. The bush is placed on the shaft flush with the thrust face of the bearing cone (7).


Using a locally manufactured tool, extract the cassette seal (3) without leaving any marks on the trumpet or external diameter of the bush (1).
Clean the groove of the seal on the trumpet and the bush (1).
Lightly smear the external diameter of the seal with Loctite 648 or equivalent and moderately lubricate its internal diameter with transmission oil.
Using service tool ref. 3378151M1, insert the seal. Wipe away any remaining traces of Loctite.
- The design of the service tool determines the position of the cassette seal in its groove in the trumpet.
Reinstall the wheel and tighten the wheel nuts or studs to the correct torque depending on the version.
Top up the oil level in the housings and check it on the transparent tube located on the left-hand side of the centre housing.
Road test. Check the oil tightness of the cassette seal.

Disassembling and reassembling the planetary gears

Remove the trumpet assembly and the epicyclic reducer gears.

Primary planetary carrier (24) 


Note visually the shape of the planetary gears (20) and roller bearings (22). Take off the circlips (29). 


Remove the three planetary gears. Secondary planetary carrier (25).
Note visually the shape of the planetary gears (28) and roller bearings (23). Take off the circlips (29). Remore the six planetary gears.
Check the components. Replace any parts found to be defective.
Install the planetary gears with their roller bearings and respective snap rings. Reinstall the planetary gears on the corresponding planetary carrier by turning the clearance "D" on the bearings towards throat "C" of the reducer gears. Install the circlips (29).
Manually check the rotation of each planetary gear.
Reinstall the epicyclic reducer gears and the trumpet assembly.

Replacing the axle shaft bearings


Remove the trumpet assembly.
Remove the brake plate, crownwheels, spacer and epicyclic reducer gears.
Take off washer (16) and shaft assembly (2).
- The bearing cone (13) is free on the shaft.
Remove cone (13). Extract bearing cone (7). Drive out the cassette seal (3).
Using an extractor or a locally manufactured tool, remove the bearing cups (8) (12). Clean and check the components. Replace any parts found to be defective. Lubricate the bores of the cups (8) (12) with transmission oil.
Insert the cups into their respective bores thrusting against the shoulder.
Lubricate the bore of the bearing cone (7) and insert it so as to mate with the shoulder on shaft (2). Lubricate the bearing cup (8).
Introduce the prepared shaft into the trumpet Installed with its cups.
Lubricate and Install the bearing cone (13) and the tab washer (16).
Reinstall the secondary planetary carrier (25), thrust washer (4), secondary sun gear (51) comprising bearing (49), washer (50) and the circlip (6).
Carry out shimming of the bearings.
Complete the refitting of the epicyclic reducer gear, spacer, crownwheels and brake plate. Reinstall the trumpet assembly.
Insert a new cassette seal.
Reinstall the wheel and tighten the wheel nuts or studs to the correct torque depending on the version.
Top up the level of the housings and check the oil level on the transparent tube located on the left hand side of the centre housing.

Shimming the axle shaft bearings

Components concerned by shimming
- Axle shaft (2), taper roller bearings (7) (8) and (12) (13), trumpet, tab washer (16), secondary planetary carrier (25), washer (4), ball bearing race (49).
- The pre-loaded shimming of the taper roller bearings of the axle shaft is carried out using shim(s) (26) placed between the end of the shaft (2) and washer (27).


- To carry out the correct shimming of the bearings, place the trumpet in a vertical position.
Check for the presence of bearing cone (13), the tab washer (16), the planetary carrier (25) and the secondary sun gear (51).

Shimming 


Press hard on the secondary sun gear while simultaneously turning the trumpet several times in order to seat the bearing cones and cups.
Using an appropriate depth gauge, measure distance "E" between side "A" of the ball bearing race (49) and side "B" at the end of shaft (2).
Determine the thickness of shim(s) (26) to be fitted to obtain a pre-loading of P1 = 0.02 to 0.12 mm, according to : E - (0.02 to 0.12)
Place the previously selected shims on the end of the shaft. Install washer (27) on ball bearing race (49). Smear bolts (28) with Loctite 242 or equivalent and tighten them to a torque of 100 - 130 Nm.