Normal Duty trumpet housings GPA40 - The planet carrier and tapered roller bearings


Removing and refitting, disassembling and reassembling the planet carrier


Removal

Tractors fitted with GTA1040 transmission
Remove the trumpet housing assembly. If possible, place it in a vertical position with the planet carrier facing upwards. Immobilise the axle shaft or the planet carrier (25).


Remove:
- the M20 screw (28);
- the tripod washer (27);
- the shim(s) (26);
- the planet carrier (25) of the ring gear.

Tractors fitted with GTA1540 transmission
Remove the trumpet housing assembly. If possible, place it in a vertical position with the planet carrier facing upwards.
Immobilise the axle shaft or the planet carrier (25).


Remove:
- the lock washer (1)
The lock washer is fixed with Loctite 401;
- the M20 screw (28);
- the tripod washer (27);
- the shim(s) (26);
- the planet carrier (25) of the ring gear.



Disassembly

Tractors fitted with GTA1040 or GTA1540 transmission


Remove:
- the screw (18);
- the spacer (17);
- the snap ring (19) by moving its two ends apart. Using a hammer, tap gently on the three pins (20). Remove the three pins and the snap ring. Remove:
- the three planet gears (22);
- the needle rollers (23);
- the spacers (24);
- the friction washers (21).



Reassembly

Tractors fitted with GTA1040 or GTA1540 transmission
Clean the planet carrier, the pins and the planet gears. Check the parts.
Smear the needle rollers with miscible grease. Fit each planet gear with two rows of needle rollers (23) separated by a spacer (24).


Fit the planet gears. Centre the friction washers (21) in the planet carrier. Imprint E on one surface of the planet gears (22) (punch mark or groove) must face the opposite way to the splined hub of the planet carrier.
Engage the three pins (20) with the snap ring (19).


Open the snap ring (19)Tap gently on the three pins so that the snap ring fits into the groove of the planet carrierManually check the axial clearance of each planet gear.


Position one end of the snap ring against the pin (20).
Clean the thread of the screw (18) and the tapped hole for this screw in the planet carrier. Fit the spacer (17). Fit and tighten the screw to 34-50 Nm, after lightly smearing its thread with Loctite 270 or equivalent.


Refitting

Tractors fitted with GTA1040 transmission 
Check that the tab washer (16) is present.
Refit the planet carrier (25). If necessary, shim the tapered roller bearings of the axle shaft. Immobilise the axle shaft (2) or the planet carrier (25).
Refit the shim(s) (26) and the tripod washer (27).


Screw in and tighten the M20 screw (28) to 374-506 Nm after lightly smearing its thread with Loctite 270 or equivalent. Refit the trumpet housing assembly.

Tractors fitted with GTA1540 transmission
Check for the presence of the tab washer (16).


Refit the planet carrier (25). If necessary, shim the tapered roller bearings of the axle shaft. Immobilise the axle shaft (2) or the planet carrier (25).

Refit the shim(s) (26) and the tripod washer (27). Screw in and tighten the M20 screw (28) to 410 Nm.

Slide a lock washer (1) onto the head of the M20 screw (28). Ensure its tabs B are correctly housed in moulded slots E of the planet carrier (25)

If this is not the case, repeat the step with the second lock washer; if this is still not the case, repeat the step with the third. Three lock washers (1) are available from the spare parts catalogue. Each of the lock washers has a 10° angular offset.

Case 1: A lock washer is selected 
Apply three spots of Loctite 401 or equivalent to the mating face of the selected lock washer which is turned towards the tripod washer (27). Loctite 401 prevents the lock washer (1) from moving when the trumpet housing is being refitted to the centre housing. When the trumpet housing is refitted, the sun gear (29) holds the lock washer in place.

Case 2: No lock washer is selected
Gently retighten the M20 screw (28), taking care not to exceed the maximum torque of 560 Nm. Refit the trumpet housing assembly.

Replacing tapered roller bearings and seals

Disassembly

Tractors fitted with GTA1040 or GTA1540 transmission
Remove:
- the trumpet housing assembly;
- the planet carrier (25).
Remove:
- the tab washer (16);
- the axle shaft (2);
- the bearing cone (13).
If necessary, extract:
- the bearing cone (7);
- the seals (5) (11) and discard them.
Using a suitable puller or a makeshift tool, extract or drive out:
- the bearing cups (8) (12);
- the friction cage (6).

Reassembly

Tractors fitted with GTA1040 or GTA1540 transmission
Clean and check all components. Replace those that are defective.
Smear the external surface of the seal (11) with a film of clean transmission oil.


Using a suitable fitting drift, fit the seal (11) to within approximately 8 mm of the shoulder of the cup (12) on the trumpet housing, positioning its lip towards the bearing cone. If a groove has been worn into the axle shaft at the location of the old seal (11), offset the new seal slightly so that its lip ensures the axle shaft is completely sealed beyond the worn groove. Fit:
- the bearing cups (8) (12) against their respective shoulders;
- the friction cage (6) according to the distance indicated:

tractors fitted with GTA1040 transmission

tractors fitted with GTA1540 transmission

Tractors fitted with GTA1040 transmission


Fit the new three-lipped seal (5) level with shoulder E of the flanged axle shaft or straight axle shaft. Fit the bearing cone against its shoulder on the flanged axle shaft or straight axle shaft using a suitable tool.

Tractors fitted with GTA1540 transmission
Fit the new three-lipped seal (5):
- 4.0 ± 0.5 mm from shoulder E of the flanged axle shaft;
- 5.5 ± 0.5 mm from shoulder E of the straight axle shaft.


Fit the bearing cone against its shoulder on the flanged axle shaft or straight axle shaft using a suitable tool.

Tractors fitted with GTA1040 or GTA1540 transmission
Lightly smear the bearing cone (7) and the lips of the seals (5) (11) with bearing grease.
Protect the seal lip (11) by temporarily masking the splines on the axle shaft with a flexible protection.
Insert the prepared axle shaft into the trumpet housing fitted with the seal (11) and the bearing cones (8) (12), positioning the three lips of the seal (5) towards the outside of the trumpet housing.
Refit:
- the bearing cone (13);
- the tab washer (16).
- the planet carrier (25). If necessary, shim the tapered roller bearings;
- the trumpet housing assembly.


Temporarily replace the plug (9) with a grease nipple. Partially fill cavity A with BP Agricharge grease or equivalent. Remove the grease nipple. Screw in the plug.

Shimming the tapered roller bearings of the axle shaft





If the following parts are to be replaced, the shimming of the tapered roller bearings on the axle shaft must be checked or carried out:

- the flanged or straight axle shaft (2);
- the tapered roller bearings;
- the trumpet housing (10);
- the tab washer (16);
- the planet carrier (25).

The preload shimming of the tapered roller bearings on the axle shaft is carried out using shim(s) (26) fitted between the end of the axle shaft (2) and the tripod washer (27)

In order to correctly shim the tapered roller bearings, fit the trumpet housing in a vertical position.

Preparing for shimming

Tractors fitted with GTA1040 or GTA1540 transmission. Fit:

- the bearing cone (13);
- the tab washer (16);
- the planet carrier (25).
- shim(s) (26) with a thickness greater than the space between the end of the axle shaft (2) and the mating face of the tripod washer (27) on the planet carrier. This should give a temporary clearance J.
- the tripod washer (27).


Temporarily lock the M20 screw (28) at:

- 374 Nm (tractors fitted with GTA1040 transmission);
- 410 Nm (tractors fitted with GTA1540 transmission).


Shimming
Tractors fitted with GTA1040 or GTA1540 transmission.
Tap the rim of the planet carrier with a plastic hammer while turning the trumpet housing by several turns.


Fit a dial gauge on the trumpet housing (10) with its feeler pin positioned near the centre of the planet carrier (25). Set the dial gauge needle to zero. Using suitable levers, move the planet carrier vertically. Measure clearance J indicated on the dial gauge. Repeat the step several times. Calculate the average of the clearance J readings.



Reduce the shim (26) thickness according to value J + (0.02 to 0.12) to obtain a preload P1 = 0.02 to 0.12 mm

If possible, shim to the maximum tolerance.


Tractors fitted with GTA1040 transmission

Definitively fit the tripod washer (27)

Lightly smear the thread of the M20 screw (28) with Loctite 270 or equivalent. 

Tighten this screw to a torque of 374-506 Nm.


Tractors fitted with GTA1540 transmission

Definitively fit the tripod washer (27)Tighten the M20 screw (28) to 410 Nm. 

From the three possible lock washers, select the lock washer (1) which will be fitted definitively.

Replacing a stud on the flanged axle shaft

If necessary, remove the wheel from the relevant flanged axle shaft. Drive out the defective stud. Clean the new stud and its housing in the flange. Lightly smear the ribbed part of the new stud with Loctite 270 or equivalent and fit it using a bronze drift and a suitable hammer.