In general, the tires on your truck rotate at different speeds, especially noticeable during cornering where the inside tire travels a shorter distance than the outside tire. To accommodate this, a device called a differential is used to divide and transmit equal torque to each tire. This type of differential is known as an open differential, and all 4WD trucks come equipped with one in the front and one in the rear.

• City & Highway Driving: Open differentials are ideal for city and highway driving where roads are flat and traction is good.
• Off-Road Limitations: However, for off-roading, open differentials are less effective. They can only divide torque between tires up to twice the amount of the lowest resistance (traction). If one tire has less traction, it receives too much torque, causing it to slip or spin-out. Once this happens, all torque is sent to that tire resulting in lost forward or rearward progress.

• Purpose: Locking differentials address this problem by providing maximum torque to each tire regardless of the traction level.
• Types: Locking differentials can be installed in both front and rear, and can be used with live axle or independent front axles.

1. Selectable Lockers: Offer the flexibility to engage or disengage the locker as needed.
2. Automatic Lockers: Automatically engage based on torque ("torque sensing") and provide reliability without the need for wiring or air systems.
3. Spool Lockers: Always engaged, providing constant power to both wheels but can make steering and tire wear challenging.

Locking differentials are essential for off-road enthusiasts who need reliable traction in challenging conditions. Whether you're out on a fishing trip or navigating tough terrains, the right locking differential can make a significant difference in performance and safety.

Selectable Lockers

Selectable lockers provide the flexibility for the driver to engage or disengage the locker as needed. This allows for maximum traction when off-road and better drivability on paved roads.

• Zip Air Locker
• ARB Air Locker
• Toyota Electric

When engaged, selectable lockers fully lock both tires together, ensuring that torque is continuously sent to each tire regardless of traction. This provides the maximum possible traction. When disengaged, the differential operates as an open differential, which is ideal for city and highway driving.

• Pneumatic (Air Operated): Uses compressed air to engage the locker.
• Electronic: Uses electronic controls to engage the locker.

• Maximum Traction: Engaging the locker ensures that both tires receive equal power, ideal for challenging off-road conditions.
• Versatility: The ability to disengage the locker provides the benefits of an open differential for on-road driving.
• Front Axle Suitability: Particularly beneficial when installed in the front axle, as it can be disengaged for improved cornering.

• Engage Only When Needed: Use the locker only when necessary to avoid unnecessary wear and to maintain optimal driving performance.

Selectable lockers are ideal for dual-use vehicles that are driven both on and off-road. They offer the most versatility and are especially useful for those who need maximum traction on demand. We recommend selectable lockers for anyone looking to get the most out of their vehicle in a variety of conditions.

Automatic Lockers

Automatic lockers are popular among off-road enthusiasts for their reliability and convenience. They don't require any wiring or air systems, making them a common choice on the trail.

• Grizzly Locker
• Spartan Locker
• Dura Grip Locker
• Detroit Locker
• TrueTrac Locker
• Lock Right Locker

When torque is applied, an internal mechanism locks both tires together. When torque is absent, the locker automatically unlocks, allowing the vehicle to corner normally. However, depending on factors like load, drag, friction, and trail steepness, the locker may stay engaged for a truck length or two, making cornering during this time more difficult.

• Simplicity: No need to worry about air leaks or wiring issues, as the locker is entirely contained within the differential.
• Reliability: Automatic engagement ensures that traction is available whenever needed without driver intervention.

• Unpredictable Engagement: Automatic lockers can engage unpredictably, especially during city and highway driving. This can cause issues like tire chirping and oversteer when turning a corner while accelerating.
• Tire Wear: Ignoring the engagement can lead to excessive tire wear and, in extreme cases, an uncontrollable spin-out.

Automatic lockers are recommended for their reliability and peace of mind, knowing they will engage automatically when traction is needed. However, it's crucial to understand their behavior for daily driving, especially in the rear differential, to avoid potential safety issues.

Spool Lockers

Spool lockers are a type of differential locker that is always engaged, meaning they provide full-time locking. The name "spool" comes from the design, which resembles a reel where each axle shaft is connected to a single, fixed spool. Originally popular in high-torque drag racing, spool lockers have gained popularity in the off-road world due to their simple and robust construction.

• Yukon Spool Locker

In a spool locker, all the traditional differential components are replaced with a one-piece spool. This design ensures that both wheels receive power at all times, preventing any speed differences between them. This means that no matter the torque or terrain, your truck will always have power distributed equally to both wheels.

• Simplicity: With no moving parts, the spool locker is incredibly strong and reliable.
• Full-Time Engagement: You never have to worry about whether it's engaged or not. Just get in and drive.

• Tire Wear: Because the spool locker never unlocks, it can cause accelerated tire wear.
• Steering Difficulty: Steering can be challenging, especially on hard surfaces, because both wheels are always turning at the same speed.
• Not Ideal for Street Use: Spool lockers are best suited for custom-built trail rigs or buggies that see very little or no on-road driving.

We do not recommend spool lockers for street use due to the increased tire wear and steering difficulties. Additionally, we do not recommended for use on the front axle.