Rear Axle Assembly

Components
(1) Left sun gear and shaft. (2) Left planetary gears (three). (3) Left planetary gear needle bearings. (4) Left planetary housing. (5) Left brake piston. (6) Drive yoke. (7) Pinion shaft. (8) Pinion tapered roller bearings. (9) Differential lock lever. (10) Right brake piston. (11) Right planetary housing. (12) Right planetary gears (three). (13) Right planetary gear needle bearings. (14) Right sun gear and shaft. (15) Left axle seal. (16) Left axle bearing. (17) Left axle shaft. (18) Axle retaining bolt. (19) Left drive axle housing. (20) Left planetary ring gear. (21) Left brake revolving disc (four). (22) Left brake stationary disc (four). (23) Differential case. (24) Differential ring gear. (25) Differential side gear (two). (26) Differential tapered roller bearings. (27) Differential lock coupling and spring. (28) Right brake stationary disc (four). (29) Right brake revolving disc (four). (30) Right planetary ring gear. (31) Right drive axle housing. (32) Right axle shaft.

The differential, rear axle and brakes receive power from the engine through the transmission and drive shaft coupling. The differential transmits this power to the drive wheels through final reduction gears and axle shafts.

This unit also contains a brake for each drive wheel and a differential lock.

Operation

Power from the transmission output shaft is taken to the differential by the drive shaft coupling and the drive yoke (6). Pinion shaft (7) is mounted in preloaded taper roller bearings (8). Differential ring gear (24) is riveted to differential case (23) and the drive from the case is transmitted through a conventional four pinion differential to sun gear and shaft (1), which is splined into side gears (25) of the differential. Differential ring gear (24) and differential assembly are partially immersed in oil thus providing adequate lubrication for bearings and bushings. Sun gear and shaft assemblies (1) and (14) project through side gears (25). This shaft ends as the sun gear of the (planetary) final reduction gear system. Planetary ring gears (20) and (30) are pressed into ring gear housings (4) and (11). Three planetary gears (2) are mounted in a carrier and are positioned around the sun gear on sun gear and shafts (1) and (14) within the planetary and ring gear. Planetary gears (2) and (12) are mounted to the carrier by shafts and rotate on uncaged needle bearings (3) and (13). The carrier has internal splines into which axle shafts (17) and (32) locate. As the sun gear and shafts are driven by the differential, the planet gears are forced to revolve inside the stationary planetary ring gear and in so doing they force the carriers to revolve at a lower speed than the sun gears.

Rear axle shafts (17) and (32) are mounted in taper roller bearings and the end play is adjusted by means of a selective shim held under retaining bolt (18). The axle shafts have flanges at the outside ends that facilitate wheel mounting.

Operator Controls
(33) Differential lock. (34) Left brake pedal. (35) Right brake pedal.

The piston actuated brakes consist of a series of stationary discs (22) and (28), and revolving discs (21) and (29), the latter of which are splined to sun gear and shafts (1) and (14). Each foot brake pedal has a brake line connected to the appropriate brake housing.

When the foot brake pedal is pushed down, the master cylinder pushes brake oil through the brake lines to the brake assembly for that pedal. Oil flows through the manifold to the oil inlet and pushes on piston (5) [or (10)]. The piston pushes against stationary discs (22) [or (28)] and revolving discs (21) [or (29)] to stop movement of the machine.

When the brake pedal is released, the seals on pistons (5) and (10) force the piston away from discs (22) and (28) releasing the brakes on the machine.

Differential Lock

With the differential lock, improved traction is possible because the lock enables additional traction to be obtained from the wheel, which is on firm ground, thus enabling the vehicle to pull through a soft spot.

Show/hide table

Do not engage differential lock when machine is moving at high speed because steering control will be limited.

Operation

Differential lock coupling (27) is located on the splines of differential side gear (25). This coupling has dog teeth which match with dog teeth on the differential lock adapter. The adapter dog teeth are in constant mesh with similar teeth machined on differential case (23). When one rear wheel of the tractor strikes a soft spot of ground and spins, the normal type of differential actions allows virtually all of the drive to be applied to this spinning wheel and little drive to the opposite rear wheel, which may be on firm ground. The result is that the vehicle is either brought to a complete stop or considerably slowed down. Depression of the differential lock foot pedal moves lever (9), compresses spring and moves coupling (27) to contact with the adaptor. As the dog teeth of the coupling come into alignment with the dog teeth in the fixed adapter, the spring tension will move the coupling into engagement with the adapter.

When full engagement has taken place (this will be noticeable by the reduced pedal pressure), the foot pedal should be released. The coupling and adapter dog teeth side forces, resulting from the transfer of power from one wheel to the other, will keep the coupling and adapter dog teeth in mesh. As the drive becomes more equally distributed, the compressed coupling spring overcomes the reduced dog teeth side forces and automatically disengages the differential lock.

Master Cylinder

Operation

Brakes Released. (1) Supply port. (2) Valve Stem. (3) Plunger. (4) Push Rod. (5) Compensation valve. (6) Bridge pipe. (7) Outlet pipe to brake piston.

Both the right and left master cylinders are the same. Fluid from the brake fluid reservoir enters the master cylinder through supply port (1). Fluid from the reservoir fills the spring chamber and outlet pipe (7) to the brake piston. Brake fluid also fills the chamber in the plunger behind valve stem (2) and bridge pipe (6). The spring and plunger (3) prevent the valve stem from closing supply port (1).

When the operator depresses one of the brake pedals, plunger (3) movement causes the fluid pressure in the plunger chamber to increase. The increased pressure in the chamber forces valve stem (2) to close supply port (1). If the operator continues to push the brake pedal after valve stem (2) closes supply port (1), the excess fluid in the plunger chamber flows around the valve stem and into the spring chamber.

After valve stem (2) blocks supply port (1), further movement of plunger (3) causes the fluid pressure in the spring chamber to increase. As the pressure in the spring chamber increases, fluid enters outlet pipe (7) to the brake piston.

As the operator applies the brake, the taper on the plunger opens the compensation valve (5). Opening compensation valve (5) allows fluid to reach the other master cylinder through bridge pipe (6). The compensation valve in the other master cylinder blocks the fluid in the bridge pipe from entering. If the operator applies both brakes at the same time, the compensation valves allow the pressure in the spring chamber of both master cylinders to equalize.

Brakes Engaged. (1) Supply port. (2) Valve Stem. (3) Plunger. (4) Push Rod. (5) Compensation valve. (6) Bridge pipe. (7) Outlet pipe to brake piston.

Oil pressure from the plunger movement closes supply passage (1) from the reservoir. Oil in the spring chamber flows to the right brake and the increased oil pressure in the system engages the brake. The taper on the plunger opens the right compensation valve and the increased pressure in the bridge pipe closes the left compensation valve.