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What Are Full Lockers On a Semi Truck?

What Are Full Lockers On a Semi Truck?

Full lockers are helpful for semi-trucks because of providing comfortable and smooth driving. It can also decrease the risk of accidents on slippery roads.

What Are Full Lockers On a Semi Truck? The full lockers in semi-trucks are a system that can lock the axle and wheels while moving on uneven road surfaces. The locking of the axle provides full traction, and wheels can move at the same speed and at the same time. This system is present in the vehicle’s cabin, and the driver can operate them by using a switch. It can be 3 way that only locks the rear axle and wheels, while a 4-way system is available for both the front and rear axle.

You should prefer the ones with full lockers if you are fond of off-roading and driving in hilly areas. This system will make your trip comfortable and safer on these uneven terrains.

What are full lockers mean in semi-trucks?

Full lockers are the advanced safety features nowadays in the new models of trucks. These are essential to provide all the torque to the tires for better traction on the road.

They will specifically lock the axles to give them full power for good wheel traction. In addition, it is also helpful for locking the wheels so they can spin collectively.

These are beneficial because all the wheels spin simultaneously and at the same speed. The movement on uneven road surfaces with these lockers gets better and more comfortable.

Types of full lockers on a semi truck

There are two types of these lockers known as 3-way and 4-way full lockers. Most of the old models of the semi-trucks have 3-way types because of less advancement and knowledge.

The 3-way are the ones that can only lock the rear end of the vehicle. The rear end means it can only control the rear axle and rear wheels while driving.

These are not better at high speed because they provide less traction and control at the turning points. It can also cause lifting at one side due to poor traction on the road.

In 3 way system, the vehicle has only one button that indicates the locking of the rear axle and wheels.

The other type is 4-way full lockers; these are the best ones and provide control of both the rear and front end.

It can engage both the front and rear axle and front and back tires during driving. With these systems, you can easily take a turn at high speed because of better control.

The 4-way system has two buttons and switches, and you have two options. You can also control the front and rear wheel and axles separately according to the driving and road conditions.

How do full lockers work in semi-trucks?

The full lockers operating system is present in the cabin of the semi-truck. It has a switch to engage and disengage the lockers.

The driver can use this button to lock the wheels and axles for better control and driving on uneven and slippery roads.

When you engage this button, the lockers will lock the axles and provide full power to both the axles for better spinning of wheels simultaneously.

Why are full lockers necessary in semi-trucks?

Full lockers are a vital part of the semi-trucks in this modern era to give people a smooth and comfortable ride.

Without these full lockers, people will face difficulty and get stuck on uneven and muddy roads for several hours.


Off-roading is different from driving on easy roads, and many people love to do this as their side hobby.

Traveling on uneven roads, which also have difficult and tricky turns, is known as off-roading. Many of my friends also plan off-roading trips once a month for enjoyment purposes.

These are difficult roads with uneven terrains; you cannot drive your trucks there without full lockers.

When you drive on these roads, one tire will start to spin faster, and the other is in the air due to poor control and traction on the roads.

The lockers will lock the axle and provide enough power to spin both wheels collectively and make the ride comfortable.

Hilly areas

Many people also plan their trips to hilly areas for enjoyment purposes with their friends and family members during the summer season.

In addition, most of the semi-trucks also have to transport the cargo in hilly areas, which is a difficult task.

In these situations, you need to engage the full lockers of your vehicle for better control and stability of the tires on the road.

It will also reduce the risk of accidents and prevent the vehicle from lifting.

Sandy areas

It is also challenging to drive in sandy areas because it can cause the slipping of tires. This is because the wheels cannot maintain their contact with the road for comfortable and safe driving.

The muddy areas also do the same thing, and sometimes the tires also get stuck in them, which can cause a problem.

When semi-trucks go there to transport cargo, it can cause an issue because of overloading.

You can fix this problem by turning on the full lockers so they can lock axles and wheels to maintain traction on the road.

During snowy season

The roads become slippery during the winter season due to the rainy season, dew drops.

Moreover, the snow falling also covers the surfaces of the roads and eventually makes driving difficult.

Due to these factors, it becomes difficult to drive the large and heavy trucks on these roads because of slipping issues.

The slipping will also occur when you apply brakes and drive at high speed, increasing the risk of collision with other vehicles.

You can minimize this problem by engaging the full lockers that can provide better control and maintain the contact of the tires with the road.

Is it safe to use full lockers on a semi truck?

The full lockers are safe to use but need special care and maintenance of speed during off-roading and driving on wet roads.


Sometimes when you engage the full lockers in your trucks, you can hear the harsh noise coming from the tires.

The harsh noise also feels like a grinding noise which can come in some types of these lockers. It also depends upon the quality of these full lockers.

The ones that have low quality can produce harsh noise while driving.

Increase fuel mileage

Driving with full lockers engaged will also increase fuel efficiency. However, it will increase your fuel cost and make it costly while off-roading.

The fuel cost will increase because the engine has to supply more power for the vehicle’s movement.

The locked axle will drain more power from the engines for the spinning of wheels than the unlocked ones.

The draining of more power will eventually increase fuel usage.

Early wear and tear of tires

There are more chances of wear out in tires when you drive with locked axles and tires.

The life of the tires will decrease, and their tread surface will also become damaged after some time.

The tires will take more energy to spin and maintain better contact with the road for easy movement on muddy and sandy surfaces.


Many of my friends who have full lockers in their semi-trucks also complained about the issue of understeer.

They said they find it difficult to move the steering wheel and apply more power than the normal routine.

Due to the engagement of full lockers, the locked axle cause movement of steering to be a little tricky.

Can you drive at high speed with full lockers?

There are no speed restrictions on driving at high speed with full lockers engaged in federal law. However, driving at a slow speed is recommended because it will put less stress on different truck parts.

In addition, when you drive at high speed with these lockers engaged, it can also cause a sudden blowout of tires and make them more vulnerable to damage.

Many people recommend the speed limit according to their experience, which cannot cause any damage or problem.

Driving at a maximum speed of 20 to 25 miles per hour is acceptable. However, you should not exceed this speed because it will also overheat the engine.

Are automatic full lockers better than manual ones?

The automatic full lockers are present in some models of the semi-trucks that automatically lock the axle and wheels.

In addition, this type also has the torque sensing function that is helpful in the spinning of both the tires at the same rate and the same speed.

These types are not under the driver’s control, and they work automatically after receiving signals of torque.

Moreover, these are worth buying because you do not need to engage and disengage them again and again while driving.

The automatic ones also start to work when one tire starts to spin faster than the other. After sensing the spinning of one tire, the automatic lockers activate and lock the axles as soon as possible.

In the manual ones, you have to press the button according to the condition of the road. Furthermore, they also need air, electricity, and wires for their appropriate work.

These are less reliable and durable than the automatic ones because the issue commonly comes in wires, air systems, and electric power sources.

Do all semi-trucks have full lockers?

 Semi-trucks are essential for loading and unloading cargo in different states of America.

The full lockers are also an essential part of these transportation trucks, but it is not necessary for all types.

These are only beneficial for those who have to go to uneven and challenging terrain to transport different materials.

It will also make transportation easy, safe, and comfortable for driers and take less time. Moreover, the risk of accidents decreases with this safety feature in the trucks.

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