The differential for the front axle has an arrangement which allows the differential to be locked and the mechanism enables the axle shafts of the universal joints to be locked together. Both wheels can then rotate at the same speed and torque regardless of different ground resistance between the wheels.
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| Illustration 1 | g00833493 |
The differential lock is controlled by a two-position foot switch that is located on the floor of the operator station.
The differential lock is controlled in the following way:
- The differential lock is engaged by oil pressure when the foot switch is held down.
- The differential lock is disengaged by spring force when the foot switch is released.
The foot switch for the differential lock control operates a solenoid valve. Oil is supplied to the solenoid valve from the charge pump for the transmission. Refer to Systems Operation/Testing and Adjusting, "Location of Hydraulic Components" for the location of the solenoid valve for the differential lock.
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| Illustration 2 | g00907223 |
Differential lock actuator (1) Fork (2) Spring (3) Piston (4) Shaft (5) Spring (6) Switch | |
Fork (1) is located on shaft (4) in the differential housing. When the switch on the floor of the operator compartment is pressed oil pressure is supplied to the solenoid valve. Oil pressure from the solenoid valve exerts pressure on piston (3). The piston moves the shaft and the fork against springs (2) and (5). This movement engages the differential lock.
When shaft (4) contacts switch (6) an input is sent to the ECM. The ECM then sends an input through a CAN data link to the dash panel. A light on the dash panel will illuminate when the differential is engaged.
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| Illustration 3 | g00907323 |
Differential lock (1) Fork (7) Collar (8) Slots (9) Side gear | |
Fork (1) moves collar (7) axially across the differential. Four pins that are located in the collar engage in slots (8) in side gear (9) of the differential in order to engage the differential lock.
In normal operation, the differential is unlocked and the axle shafts are free to rotate at different speeds. The wheel speed is governed by the resistance at the wheel.
Fork (1) and collar (7) are held clear of the differential by springs (2) and (5) when the differential is unlocked. Refer to Illustrations 2 and 3.