Meritor Main Differential Lock Operation
To lock the main differential and obtain maximum traction under slippery conditions, move the control switch to the lock position.
Warning: Lock the main differential only when the vehicle is standing still or moving less than 25 mph (40 km/h). Never lock the main differential when the vehicle is traveling down steep grades or when the wheels are slipping. This could damage the differential or lead to loss of vehicle control, causing personal injury and property damage.
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 differential to fully lock.
If the vehicle is moving, maintain a constant vehicle speed while engaging the differential lock. Briefly let up on the accelerator to relieve torque on the gearing, allowing the differential to fully lock. The indicator light should come on and the buzzer should sound on vehicles so equipped. When the differential is 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 Differential is Locked (engaged)—Understeer Condition
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Turning Radius When Differential is Unlocked (disengaged)
Fig. 1, Turning Radius
To unlock the main differential, move the control switch to the unlock position. Briefly let up on the accelerator to relieve torque on the gearing, allowing the differential to fully unlock.
Note: If the differential lock system is connected through the low speed range of the transmission, shifting out of low speed range will also unlock the differential.
When the differential lock disengages, the indicator light will go off and the buzzer will stop.