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Repair of AG150/AG250 transmission – Disassembling the MF 8280 tractor powershift gearbox

The Massey Ferguson 8220, 8210, 8280 tractor is equipped of John Deere AG150/AG250 transmission.

- Separate the tractor between the gearbox and the intermediate housing.

- Separate the gearbox from the engine.

Disassembling the Powershift gearbox

- Separate the tractor between the gearbox and the intermediate housing.

- Separate the gearbox from the engine.

- Take off the Gerotor pump from the gearbox and PTO shaft from the rear of the gearbox. The Gerotor pump is fixed to the rear housing of the gearbox by six bolts. Slide the pump and shaft apart to separate them. Keep the O’rings between the pump and the rear housing.

- Remove the MF 8280, 8210, 8220 tractor engine speed sensors, forward speed sensor and the calibration sensor from the gearbox in order to avoid damage to them when separating the housings.

- Remove the hydraulic supply pipes, the output connections to the oil cooler and the pressure regulating-valve from the front housing of the gearbox in order to gain access to the housing bolts.

- Place a wooden plank of the correct thickness on the ground. Provide enough space in order to be able to reach the top of the gearbox with workshop crane or a suitably adapted lifting tackle.

- In order to protect the mating faces from scratching or damage, before removing the front housing, position the gearbox vertically using a suitable sling and lifting rings ATP 3016, the rear face being placed on the wooden plank.

Removing the front housing

Raise the front housing after having removed the bolts.

Adjust the lifting sling in such a way that the front housing remains horizontal during the separating operation. The shafts will be withdrawn more easily from the housing if the latter is shaken lightly as it is lifted.

Take care that the transmission shafts remain in the rear housing and are not lifted at the same time as the front housing. Lightly shake the front housing when it is lifted to avoid bending the shafts.

Removing Massey Ferguson 8280, 8210, 8220 tractor clutches and transmission Shafts

Clean the work area and prepare shaft support plate (ATP 3019) on which the work will be carried out. The workshop must be accessible by a workshop crane or suitable lifting tackle.

John Deere AG150 transmission gearbox - Stands screwed directly into the plate

AG 250 transmission gearbox - Stands screwed into the bushes

- Remove the seal rings from all shafts to avoid damaging them before installing the shaft-lifting tool.

- Install lifting tool (AP 3017) on the shafts and fix each shaft to the tool with the supplied locking devices.

Place the lifting ring of the tool in the correct position.

- AG 150 transmission gearbox

- John Deere AG250 transmission gearbox

- With a workshop crane or suitable lifting tackle and a chain attached to the lifting ring of the tool.

- Gently raise, while lightly shaking the shafts so that the bearings leave the bores of the rear housing. Take care not to lift the rear housing at the same time in order to avoid bending the shafts.

- Once the block of shafts has been removed, take off the plastic guard from the forward pinions.

- lace the tool and shafts in a single block on the workbench.

- Position the block of removed shafts on the previously prepared support (ATP 3019).

- Remove the shaft lifting tool after having positioned the shafts on the support. Take care not to knock over the block of shafts or clutches when removing the lifting tool.

- Mark the location of the shafts in order to understand how to reassemble them.

- The shafts may be removed one by one from the support to carry out even greater levels of disassembly.

- For the repair of clutches and shafts.

Replacing the input shaft seal

Replacing the seal only without disassembling the MF 8280, 8210, 8220 tractor gearbox

Fig.46

- Separate the Massey Ferguson 8280, 8210, 8220 tractor between the engine and gearbox.

- Take out, by sliding them, the input shaft and the spring from the gearbox.

- Take out the input shaft seal through the front housing of the gearbox using a suitable extractor.

- Install a new seal using an insertion sleeve.

- Take care that the new seal is correctly aligned so that it does not leak. Lubricate the seal lip with miscible grease.

- Reassemble in reverse order using the guide studs to align the gearbox with the engine.

Replacing the seal while disassembling the MF 8220, 8210, 8220 tractor gearbox

Fig.47

- When the front housing (1) has been removed, take out the old seal (41).

- Install the new seal using a suitable insertion sleeve, taking care that it is correctly aligned so that it does not leak. Lubricate the seal lip with miscible grease.

Inspecting and repairing the housing

Inspecting the housing

- Examine all the bearing bores of the front and rear housings to ensure that they are not damaged. Replace or repair any damaged bores.

- Examine all wear rings for damage and replace where necessary.

Fig.48

Replacing seal wear rings

All the seal bores in the front housing contain rings. The latter may be replaced if they are damaged. The location of the holes in the rings is not very important since the bores have annular grooves beneath all the bushes.

By using an extractor with two or three jaws and fitted with an inertia device, hook the front edge of the ring and extract it. Fit a new ring leaving the chamfer on the outside to guide the seal. Fit the new bush by pressing the insertion sleeve against the housing.

Lubricating relief-valve

If the previous tests have shown that the lubricating relief-valve is defective (10), it may be removed from the interior at this time. It may also be removed from outside the housing by taking off the oil cooler piping and connection. Screw tap the inside of the valve (10) (Fig. 26) and use an inertia extractor to remove it.