Front Driving Axle

1 – driven bevel gear; 2, 15, 28 – adjusting shims; 3 – steering knuckle pivot spindle; 4 – bolt; 5 – cap; 6 – lubricator; 7, 10, 16, 27 – rubber ring; 8 – sleeve; 9, 34, 35 – taper roller bearing; 11, 32 – collar; 12 – fixture; 13 – half-axle shaft; 14 – left-hand housing; 17 – breather; 18 – differential; 19 – driven bevel gear; 20 – nut; 21 – FDA casing; 22 – right-hand housing; 23 – washer; 24 – pivot; 25 – plug; 26 – draining plug; 29 – driving gear carriage; 30 – adjusting washers; 31 – wiper ring; 33 – nut; 36 – driving bevel gear; 37 – lock nut; 38 – screw; 39 – filling plug; 40 – draining plug, 41 – filling plug, 42 – lubricator.

The front driving axle is intended for transmitting the torque from the engine to the front steerable wheels of the tractor. It consists of the final drive, differential and wheel reduction gears. The left-hand (14) and right-hand (22) housings connected with the front driving axle casing (21) by means of bolts form the front axle beam. The front driving axle casing is provided with a breather (17) maintaining the normal pressure in the cavity of the axle and final drive beam.

The axle beam is filled with oil to the lower edge of the filling opening through the plugs (41) installed in the housings (14) and (22). To drain oil from the axle beam, screw out the draining plug (26) located in the front driving axle casing. Oil shall be fed through the opening in one of housings until the lubricant in another housing reach the lower edge of the filling opening. The front driving axle shall be filled with oil on a horizontal surface.

The front driving axle casing (21) is connected with the beam by means of the pivot (24), on which the axle with the wheels can swing in the cross plane while deflecting to the angles limited by the stops of the ribs in the housings (14) and (22) when they contact the tractor beam. The pivot is locked against axial displacement by means of the washer (23). The pivot is greased through the lubricator (42).

Final Drive

The final drive is a pair of bevel helical gears.
The driving gear (36) of the final drive is mounted in the carriage (29) on two taper roller bearings. The tightness in the bearings is adjusted by means of adjusting washers (30), after which they are tightened by means of the nut (33). The driven gear (19) is fitted on the splines and centring spigot of the differential casing (18) and locked against axial displacement by means of the nut (20).

The final drive mesh is adjusted by means of the adjusting shims (28), (15) placed between the flange of the driving gear carriage and front driving axle casing as well as between the left- and right-hand housings and front driving axle casing, respectively. Before adjusting the mesh, the differential bearings shall be adjusted by means of the shims (15).

The opening for the plug (25) serves for checking the adjustment of the final drive mesh.
Oil leakage from the cavity of the final drive and axle beam is prevented by using the collars and rubber rings placed in the fixtures, housings and driving gear carrier.
To prevent the oil up-thrust up-stream the collar of the driving gear, the latter’s splined end is fitted with the wiper ring (31) with spiral groves cut over the outer diameter of the ring. A slide bearing with crossed grooves is mounted in the fixture (12).


The differential is self-locking, with increased friction. The casing (1) and cover (7) of the differential bolted together contain the two pairs of satellites (6) on floating pins (5), axle-shaft gears (8), pressure cups (4) as well as driving (2) and driven (3) friction disks.

The self-locking differential connects automatically both the axle shafts and excludes separate skidding of the wheels that increases the tractive force of the front wheels. The locking takes place when the front axle is engaged.
At that moment, the satellite shafts turn under load and move over the bevel slots in the casing and cover of the differential, respectively, by the value of the clearances between the friction disks.

From the pins, the force is transmitted to the satellites which, in turn, transmit it through their beads to the cups, and the latter press the friction disks against one another until they rest against the walls of the casing and cover of the differential. The driving plates having the outer teeth are in mesh with the teeth of the casing and cover of the differential and the driven plates (through their inner teeth) – with the axle shaft gears. The friction force of the pressed together disks unites the axle-shaft gears and casing with the cover of the differential into a whole while locking in such a way the differential.

1 – differential casing; 2 – driving plate; 3 – driven plate; 4 – pressure cup; 5 – satellite shaft; 6 – satellite; 7 – differential cover; 8 – axle-shaft gear; 9 - taper roller bearing.

When the front axle is engaged and the external forces exceed the friction forces in the friction disks during the turning of the tractor, the friction disks will skid.

The differential is installed in the two taper roller bearings in the housings of the front axle beam. The bearings of the differential are adjusted by means of the shims 15 (see Figure “front driving axle”).