Operation of the Differential Lock
Warning: Locking the wheels when the vehicle is traveling down steep grades or when the wheels are slipping could damage the differential and/or lead to loss of vehicle control, causing personal injury and property damage.
Notice: The differential lock should be engaged when the vehicle is stopped or moving at a low, constant speed and the wheels are not spinning, slipping, or losing traction. Engagement at high speed or power can damage the axle(s).
Do not permit rear wheels to spin freely for more than ten seconds when traction is lost. Shift into lock to prevent damage to interaxle and main differentials.
Lock the wheels only when the vehicle is standing still or moving at very low speed, less than 5 mph (8 km/h). Never lock the wheels when the vehicle is traveling down steep grades or when the wheels are slipping.
Note: On some vehicles, the differential lock system is connected through the low speed range of the transmission. If this system is used, the transmission must be in the low speed range for the wheels to fully lock.
Warning: A vehicle with locked wheels can still slip sideways, causing possible loss of vehicle control, personal injury, and property damage.
Be especially careful when driving under slippery conditions with the wheels locked. Though forward traction is improved, the vehicle can still slip sideways.
If the vehicle is moving, maintain a constant vehicle speed when the differential lock is turned on. Briefly let up on the accelerator to relieve torque on the gearing, allowing the wheels to lock completely. When the wheels are fully locked, the turning radius will increase because the vehicle understeers. See Fig.. Drive cautiously and do not exceed 25 mph (40 km/h).
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Turning Radius When the Differential Lock is Engaged (understeer condition).
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Turning Radius When the Differential Lock is Disengaged.
Fig. 1, Turning Radii
To disengage the differential lock after leaving poor road conditions, press the upper half of the switch, while maintaining vehicle speed. Let up momentarily on the accelerator to allow the wheels to fully unlock, then resume driving at normal speed.
Note: If the differential lock system is connected with the transmission in its low speed range, shifting out of the low speed range will also disengage the differential lock function. The switch will blink until the wheels unlock, and then go out.