Diff Lockers and How Do They Work

Look at any vehicle on the road and you will see at least one differential. Virtually every vehicle built since the 30’s has a differential attached at the drive shaft. And why would they not? Differentials allow for cornering, different wheel speeds (hence the name), power distribution and are responsible for the invention of 4WD’s. If so crucial a part, why would we want to lock them?

Why would you want a differential to lock up?

The purpose of a differential is to allow wheels to spin at different speeds while being connected to the drive train (power source). On bitumen, this is crucial to steering, traction and power delivery because when steering, the outer wheels travel a longer distance, and as a result, spin faster. The differential automatically shares proportionally more power to the faster spinning wheels, ensuring grip and power are where they are needed.  However, when off road, this suddenly becomes a disadvantage.

When would you use your diff lock?

Off road driving often travels into soft or uneven ground. In these moments, when a wheel hits soft sand or hangs in the air, the diff sends all the power into the fast spinning wheel. This means your vehicle bogs down (soft) or loses all driving power (air). This is when a locking differential makes all the difference.

By locking the differential, the wheels spin at the same speed, no matter what surface or resistance is offered. This enables the opposite wheel, in combination with the vehicle’s momentum, to continue gripping and move past the obstacle.

How do they work?

A differential is essentially an additional set of gears where the driveshaft meets the wheel axle. The part that connects the driveshaft with the differential is called the ring gear. A diff lock is two parts, one attached to the wheel axle, and the other attached to the ring gear. When engaged, a diff lock diverts the power from the ring gear directly to the axle, missing the differential altogether. On most 4wd setups, the vehicle will have three differentials. One each for the front and rear axles, and a third ensuring both front and rear spin at the same speeds.

Just remember, you don’t want to lock your differential when already bogged, or leave locked when back to firmer grounding. This can apply excess strain on the driveshaft and perhaps cause damage.

Diff locks are an important part for any vehicle tackling serious off-road tracks. Most 4WD available come with a lock as at least a factory option. If not, there are a range of high-quality after-market diff lockers available.

In the market for an upgrade to your 4WD? Maybe you are having issues with your transmission? At WA Diff Centre we have spent over 20 years specialising in conversions, installation, repair, reconditioning or any other work on differentials and transmissions. Contact us today, and experience what first class customer service feels like.

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