Do Rear Differentials Need Locking?


Did you recently purchase a four-wheel-drive vehicle? Maybe you already have one but are planning on going on an adventure where you will truly be depending on its off-roading ability. One aspect to check on your vehicle is the differentials. Deciding to lock them can really help you out while off the trail.

Rear differentials allow your vehicle to turn properly. The main job of a differential is to send energy from the engine to the tires. Locking your rear differentials allows the driver to place the vehicle in lock mode while off-roading to enhance the stability of the car.

Now that you know some of the reasons behind this feature, you may wonder how can you lock your differentials, and what benefits you can gain from this.

What Are Differentials?

When your vehicle turns, the wheel on the outside turns faster and further than the inside wheel. Differentials in your vehicle allow this to happen. It signals to the engine how much power to give to the wheels to allow you to steer and direct your vehicle safely and properly. Without differentials, you would be unable to steer and would be stuck going in a straight line.

Depending on the drive type of your vehicle, the differentials are located in different areas. Front-wheel-drive vehicles have the differential located near the transmission in a unit called a transaxle. Rear-wheel-drive vehicles locate their differentials between the rear tires.

The differential is then connected to the transmission through a driveshaft. All-wheel-drive and four-wheel-drive vehicles have their differentials in the center to allow power to be given to the front and the rear of the vehicle.

What are the different types of differentials?

Open Differentials

This is the standard type of differential. Most modern and regular vehicles are equipped with an open differential. This sends information to the engine to send power to the axles to spin the tires are different speeds. This tells the engine to send more power to the outside turning wheel to create a proper turn.

Usually, the outside wheel will have the least amount of traction as it makes the turns, going faster and further. This type of differential works perfectly fine for on-road driving and the everyday driver. Most two-wheel-driving vehicles are equipped with this type of differential.

Locked Differentials

Locking differentials allow both wheels to spin at the same speed. This helps when one wheel loses traction, the other will continue spinning to get you where you need to be. Locking differentials can either be in the front or the rear, or in some cases, both.

This is great for those who plan on off-roading and taking their vehicle to the extreme. According to a professional who works at Grease Monkey, a local mechanical shop, rear locking differentials are very beneficial for those who plan on off-roading frequently. They allow the driver to have more traction and control over the vehicle as you go over the uncontrollable.

Locking differentials help when the road (or off-road trail) you are driving on is extremely uneven or has little traction. While open differentials may cause the vehicle to stop moving or spin out, locking differentials force both wheels to continue spinning, allowing you to go places uncharted (at least by those in open differential vehicles).

There are two main different Locking Differentials. Those are automatic and selectable differentials.

Automatic Differentials

Automatic differentials are very self-explanatory. Vehicles with automatic locking differentials do not have to manually turn on and off the differentials. They turn on depending on the driving conditions. It is important to note that some automatic locking differentials on constantly on, and only turn off when driving conditions are at a certain stableness.

Automatic locking differentials that stay in a locked position until acted upon from outside force are great for off-roading. On the other hand, they can be very dangerous for regular street driving. The reason for this being the tires do not have the ability to spin at different speeds. This could potentially cause you to spin out or tip over in extreme situations.

The other kind of automatic locking differentials is the complete opposite. This type of automatic locking stays in a neutral, open position until the driving conditions signal the differential that they need to lock. This is great for drivers who enjoy off-roading but do not go enough to purchase selectable differentials.

This type of locking differential also prolongs the life of your tires, by not having the unnecessary everyday strain of being locked.

Selectable Differentials

Similar to “automatic differentials”, selectable locking differentials are self-explanatory. This type of locking mechanism is up to the driver when it gets turned on and off. In modern vehicles, electric switches allow the driver to turn the locking on and off, in older vehicles, cables or air lockers are equipped to accomplish the same thing.

In vehicles that have cable or air lockers to allow the selectable differentials to work, drivers should know that the mechanism may fail over time and need to be looked at to ensure they work properly.

Being able to turn on the locking of your differentials at your own will is extremely useful for drivers. Especially if you frequently go off-roading, having the ability to equally distribute the power between the tires offers the driver a better experience.

Pros Of a Locking Differential

Before we look at the list of pros of having locking differentials, it is good to note that selectable locking differentials have more benefits than their automatic counterparts. Being able to turn off and on the locking prevents wear and tear will still giving the driver the same benefits of having locking differentials. Other benefits include:

  • Enhanced off-roading performance
  • Distributes power evenly to all wheels
  • Improves traction in rough terrain

Cons Of a Locking Differential

Unlike the selectable locking differentials, automatic locking differentials cause unnecessary wear and tear to your tires when you may not even need your differentials to be locked. Other cons of locking differentials include:

  • Higher cost for selectable lockers
  • Complicated to fix if break
  • Some cause loud and weird noises while making tight turns

Will Turner

Will has an absolute passion for 4x4s and loves discovering all of the small details about each model. Will joined the Four Wheel Trends team in early 2021 and has been a valuable contributor ever since!

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