Specifications, Service and Repair of Farm and Lawn Tractors


Massey Ferguson 8110, 8120 gearbox - Input unit with mechanical reverse shuttle

The input unit transmits the movement from the MF 8110, 8120 tractor engine to the transmission via the clutch (Pressure loaded). It is in the form of an interchangeable module installed on the gearbox inlet.

It comprises two quite distinct parts: the Dynashift and the reverse shuttle.

The Dynashift is fixed to the front of the input unit. The reverse shuttle is located in the rear cavity of the input unit.

Removing and refitting the unit

Massey Ferguson 8120, 8110 tractors may be fitted with a Heavy gearbox comprising an input unit with a Dynashift and a reverse shuttle.


Split the tractor between the engine and gearbox. Drain the gearbox.

Remove the selector cover. Remove selector.

Remove the clutch assembly. Remove the direct drive shaft.

Remove the clutch control valve without disconnecting the hose coming from the master-cylinder as well as the transfer tubes connected to the unit (lubrication and 17-bar pressure).

Install adapter plate, on cover (13), using four screws A of the correct length, then fix sling, on the plate as shown in Fig.

A - Attachment of adapter plate on front cover, B - Avoid removing screws

Remove the screws fixing the unit to the MF 8110, 8120 gearbox. Unstick and pull the input unit towards the front.

Assisted by an operator, open the selector cover and check that the selector rails come free of their front support.

Tilt the unit fully downwards to allow the support to pass through the bore in the gearbox.

Retrieve locating pin. Place the unit on a work bench in the vertical position.


To facilitate engagement of input unit end bearing (1) into the gearbox layshaft, coat the bearing rollers with miscible grease to stick them in place. Insert locating pin.

Screw two guide studs (L = 80 mm) in opposing locations on the gearbox housing (optional). Using sling, and adapter plate, engage the input unit in the clutch housing. Tilt it fully downwards to allow the selector rail support to pass through the front bore of the gearbox.

Assisted by an operator, check through the opening in the selector cover that the selector rails correctly engage in the front support. Use sleeve, to turn shaft (7) in order to facilitate meshing of the pinions.

Position the unit on the locating pin. Remove the guide studs (if installed). Torque the screws securing the unit to the gearbox housing, to a value of 39 - 54 Nm.

Remove the sling then proceed to assembly of the Dynashift front cover: coat the four original screws (temporarily replaced by screws "A") with Loctite 241, then install and torque to 29 - 37 Nm. Reinstall the clutch control valve and the transfer tubes (lubrication and 17-bar).

Refit the direct-drive shaft. Refit the Massey Ferguson 8110, 8120 clutch.
Refit reverse-gear selector. Coat the screws with Loctite 221 and torque to 35 Nm. Refit the selector cover.
Reassemble the tractor between the engine and gearbox.
Service the oil in the sumps and check the level in the sight glass located on the left of the centre housing.
Bleed the clutch control if necessary.
Proceed to road-test of all Dynashift controls and gear ranges A, B, C and D.
Check for leak tightness at couplings and mating face of selector cover.