What Is an Automatic Locking Rear Differential?

by Shoaib Khan
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The differential is a drivetrain component that is used to transfer power from the engine to the wheels. While a differential usually allows each rear wheel to rotate at different rates, automatic locking rear differentials "lock" the rear wheels, forcing both to rotate at the same speed.

Open Differential Drawback

Locking differentials address the problem with open differentials, which are the most basic type. In an open differential, when one wheel of an automobile is slipping and the other is firmly in place, most of the power from the engine is carried to the slipping wheel. This makes the wheel spin faster and faster, while the other one receives no power.

Locking Differential

An automatic locking rear differential solves the problem presented by the open differential by using a mechanism that locks the rotation of one wheel relative to the other. No matter how much traction (or how little) a wheel has, it will be forced to rotate in sync with the other.


In the automatic locking differential, both wheels of an axle are locked relative to one another on applying torque. When torque is not applied, such as when turning a corner, the lock disengages, allowing the wheels to spin independently.


Since the mechanism locks and unlocks the wheels automatically, automobiles with automatic locking rear differentials have distinct handling characteristics.


Another kind of locking differential is known as on-command, which is a manually operated mechanism and only engages the lock when a switch is turned on.

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