What is a Differential Locking

A locking differential provides increased traction compared to a standard, or “open” differential by disallowing wheel speed differentiation between two wheels on the same axle under certain conditions. A locking differential is designed to overcome the chief limitation of a standard open differential by essentially “locking” both wheels on an axle together as if on a common shaft while still allowing them to rotate at different speeds when it is required (such as when negotiating a turn).

This forces both wheels to turn in unison, regardless of the traction (or lack thereof) available to either wheel individually. An open differential will cease the transmission of torque to one wheel if the opposite wheel has little or no traction.

This may occur if one wheel comes into contact with mud, snow, or ice, or if the wheel is somehow removed from contact with the road after encountering an obstacle or area of soft ground. In such a situation, an open differential will continue to spin the wheel with the least amount of traction but will transmit little or no power to the wheel that has more solid traction.

Basically, it will transmit only as much torque to both wheels as the wheel with the least amount of traction can sustain. This can result in the vehicle failing to deliver enough torque to the drive wheels to keep the vehicle moving forward, at which point it will be stuck. The diff lock forces all wheels to spin at the same speed, regardless of traction. This is helpful if you encounter difficult terrain and one or more wheels leave the ground, as full power remains on the other wheels ensuring you are still moving in the direction of travel.

For example, let’s say you are driving over rocky terrain and one of your wheels leaves the ground. This may be the wheel that has the most driving power, leaving the other three wheels struggling to get enough traction to push the vehicle forward. A locking differential ensures that maximum power is put into all wheels, providing a much needed boost to your forward propulsion. Therefore, your differential lock provides a traction control system and is a key component to preventing wheel spin, which can prove a life saver in treacherous driving conditions, such as snow or ice.

LSD (Limited slip differential) works by limiting the independence between right and left axles. The most common Limited Slip Diff technology is clutch-pack based or pre-load spring based. It consists of a series of friction and steel plates packed between the side gear and the casing.

This technology works by allowing the wheels to function normally on the tarmac and high traction surfaces without having to engage or disengage anything. The wheels are allowed to turn at different speeds like when taking corners but will lock up when driving in a straight line and the clutch pack or metal plates detects it is in a high-torque situation.

The torque coming from the drive shaft then forces the diff closed. It sounds good in theory, however, it is not as effective as a differentials locker or even a modern TC system. It is, however, better than just an open differential.