Specifications, Service and Repair of Farm and Lawn Tractors


AG250/AG150 transmission - Reassembling the Massey Ferguson 8250 tractor gearbox

- After cleaning the housings and refitting the Massey Ferguson 8250, 8260, 8270 tractor gearbox shafts and clutches, place the rear face of the rear housing on the suitably sized plank of wood.

- Install the pinion block lifting tool (ATP 3017) on the shafts in supporting tool (ATP 3019).

- Take care that each shaft is locked to the lifting tool. With a workshop crane or suitable lifting tackle, move the block of pinions towards the rear housing.

- Install the plastic guard on the pinion block. Slowly lower the pinion block into the rear housing taking care that guard remains in place.

- When the pinion block approaches its original position, take care that all the bearings are correctly placed in their respective bores.

- Once the shafts begin to slide into their bores, lightly shake the pinion block so that the bearings slide into the bores.

- Take care that all the shafts attain their original position. Remove the pinion block lifting tool.

- Before fitting the seals on the shafts. Reshape each seal ring by holding it and joining both ends and compressing them so that the ends overlap. Fit the seals on the shafts and centre them in the grooves.

- Apply miscible grease on the outside of the seal to maintain them more easily in the groove. Check that all the seals are correctly placed on each shaft.

- Using lifting rings (ATP 3016) fitted to the front housing, lift the housing to a horizontal position to place it above the shafts of the rear housing.

- Clean and degrease the front and rear housing flanges. Use Loctite 518 to seal the front and rear housings.

- Install the guide studs (ATP 3022) into the rear housing to facilitate the installation of the front housing.

- Lower the front housing onto the rear housing. Lightly shake the front housing shafts, taking care that it is perfectly horizontal when it is lowered. This avoids damaging the seal rings when lowering the housing.

- Install the 16 x 140 mm retaining bolts in the housing and tighten them one by one to a torque of 68 Nm. Then tighten to 135 Nm. Finally tighten to 217 Nm.


- Install the pressure regulating-valve (11), oil cooler pipe connectors and the speed and calibration sensors in the housings.

Overhaul a MF 8250, 8260, 8270 tractor speed clutch train

- All speed clutch trains are disassembled in the same manner.

- All speed clutch trains are composed of two clutch packs.

The sets of speed Massey Ferguson 8240, 8250, 8270 tractor clutches are identified thus:

- clutches A and 2 - 2nd stage shaft
- clutches B and R - 3rd stage shaft
- clutches C and 1 - 4th stage shaft

- For more details on the fitting of each shaft, see the inspection the transmission components.

- Using a clutch train sling (ATP 3021), remove the speed clutch to be repaired from the pinion block support tool. Place the clutch train on a clean workbench and turn the groove of the seal ring upwards.

Take care that the gear train is properly supported to avoid it toppling and damaging the pinions.

- Install a split bearing extractor (OEM 4175 or equivalent) on the bearings. The split bearing extractor must be fitted so that its flat surface is turned towards the pinion.

- Tighten the tightening bolts of the extractor until the bearing begins to extract.

- Hook the pinion extractor below the split bearing extractor and extract the bearing from the shaft by pulling.

- Remove the circlip from the shaft.

- Place the extractor (ATP 3030) on the pinion and tighten the bolt. To be able to remove the pinion from the shaft, the extractor must be tightened around the external diameter of the pinion.

- In some cases, the main sleeve is necessary and must be fitted beneath the pinion. Place the extractor by hooking it beneath the sleeve and extract the pinions and the bearing from the shaft by pulling.

- To select the extraction sleeve that matches the pinion, see the pages relating to the clutch trains.

- Remove circlip, closing plate, thrust plates and friction plates.

- Install a suitable extractor on the bearing of the inside pinions and remove the latter from the shaft.


- Place the clutch train in a press. Fit tool ATP 3002 on the Belleville washers. Compress the washers, remove the circlip and release the pressure on the washers.

- Remove the Massey Ferguson MF 8250, 8260, 8270 tractor clutch train from the press and remove the locking washer from circlip (11) and the Belleville washers (10).

- Remove the oil seal washer (9) that lies between the Belleville washers (10) and the clutch piston (6).


- Once the Belleville washers are removed, inject compressed air into the clutch oil supply channel near the seal ring on the shaft (24) or (25). This will eject the piston from the clutch housing (1).


- Disassemble the opposite end of the shaft in the same manner.

The best method to maintain the shaft in a vertical position is to have a 3” (76 mm) diameter hole in the workbench to recieve the shaft.