Locker

In general, the tires on your truck rotate at different speeds. This is most apparent during cornering where the inside tire travels a shorter distance than the outside tire. Because of this, a device called a differential is used to divide and transmit equal torque to each tire. We will call this an open differential, and all 4WD trucks are built with one front and one rear differential. Open differentials are useful for city & highway driving, where the road is flat and traction is good, but they are not good for Rock Crawling.

For Rock Crawling, the open differential is undesired because it is only able to divide torque between each tire up to twice the amount of the lowest resistance. Therefore if one tire experiences less than half the traction of the other, it will receive too much torque and will lose or break it's traction. Once this happens, all torque is sent to the lose tire since it now has very low resistance, and thus forward progress is lost. Enter Locking Differentials. Locking differentials reduce or eliminate this problem by providing maximum traction to each tire in all conditions regardless of how much traction each tire has.

In most applications, Locking Differentials may be installed in front and/or rear, live axle or independent front axles. We offer three types of Locking Differentials: Selectable, Automatic, and Spool.

Click here for Selectable Locker info...

Selectable Lockers offer the driver the option of engaging or disengaging the locker. Once engaged, both tires are fully locked together so that torque is continuously sent to each tire regardless of traction. This results in the maximum possible traction. Once disengaged, the differential becomes open as described above, which is preferred for city & highway driving. We carry pneumatic (air operated) as well as electronic selectable lockers. The best practice is only to engage the locker when needed and this is only possible with a selectable locker. We recommend selectable lockers for dual-use off-road and on-road vehicles, or for anyone seeking the most versatility from their rig. Selectable lockers are great when installed in the front axle because it can be disengaged for maximum cornering potential.

Click here for Automatic Locker info...

Automatic Lockers offer the driver reliability and convenience without the hassle of wiring and/or an air system. This is the most common form of lockers on the trail today. When torque is applied, an internal mechanism locks both tires together. In the absence of torque, the locker automatically unlocks. This allows the vehicle to negotiate corners as normal, however in some situations based on load, drag, friction, and steepness of the trail, the locker may remain engaged making it difficult to corner. The locker is entirely contained within the differential, so you don't have to worry about air leaks or wiring trouble. Therefore, we recommend automatic lockers for their reliability and peace of mind: You know it is there and will engage automatically whenever traction is needed.

IMPORTANT for daily drivers: Automatic lockers, by their very nature, may engage in an unpredictable manner. This characteristic is important to understand for city & highway driving with automatic lockers installed in the rear differential. For example, if you are driving in the city and you turn a corner while accelerating, the locker will automatically engage causing both tires to rotate at the same speed. Your truck will likely chirp it's inside tire which may cause oversteer. If the driver ignores this, it will lead to excessive tire wear, and in extreme cases, it could lead to an uncontrollable spin out.

Click here for Spool Locker info...

Spool Lockers are a full-time, always engaged locker. Its name is derived from the very nature of a spool, or a reel, in which each axle shaft is attached to a fixed one-piece spool. Commonly found in high torque drag race applications, spool lockers have found their way into the off-road world due to their simple and robust design. The traditional components that make up the differential are entirely replaced by the Spool Locker. This results in a full-time engagement preventing any speed differences between each tire. Your truck will always have power to both wheels regardless of the torque being applied and regardless of the terrain. There are no moving parts, it is a strong, one-piece design, and you never have to worry if it is engaged or not. By far the simplest form of any locker, simply get in and drive. The draw back to the spool locker is that it never unlocks! You will always wear out tires sooner and you will always have difficulty with steering. The spool locker is mainly intended for custom built trailed rigs/buggies that will see very little or (ideally) no on-road driving. We do not recommend spool lockers for street use and we rarely recommend spool lockers for front axle use.

Grizzly Locker

The Grizzly Locker is an automatic locker that replaces the entire carrier assembly. It is the strongest automatic locker we offer. Using modern technology, the Grizzly Locker is designed from the ground up with a patent-pending internal locking mechanism providing unmatched strength. It's advanced design has resulted in a robust yet easy-going product. Compared to other automatic lockers, the Grizzly Locker has a softer engagement/disengagement thanks to a freely-rotating component design complete with an improved teeth engagement profile. Comes with a one year unconditional warranty!

Zip Air Locker

The Zip Air Locker is a selectable locker similar in design to the ARB Air Locker (listed below), but at a more competitive price. The Zip Air Locker is based on a proven design that Marlin has used since the late 1980's, featuring a strong forged nodular case with high-nickel 4320 Chromoly steel internals for excellent strength and durability. The Zip Air Locker works with air pressure and fully locks or unlocks your differential at the flip of a switch. Includes a complete installation kit and works with a variety of air delivery systems. Recommended for any type of Rock Crawler. Comes with a two year unconditional warranty!

ARB Air Locker

The ARB Air Locker is a selectable locker that replaces the entire carrier assembly. Made in Australia, ARB has an extensive reputation for making high quality products that have been featured in all levels of off roading. Developed in the early 1980s, the ARB Air Locker uses air pressure to engage and fully lock both drive axles for maximum traction. The locker is operated by an interior mounted switch. On board air is required as well as solenoid and switch wiring.

Spartan Locker

The Spartan Locker is an automatic "drop-in" locker, meaning that it installs into your factory carrier assembly rather than replacing it. Like the Grizzly, the Spartan Locker is an improvement upon older designs. Made in the USA, it features a revolutionary spring-and-pin design that makes it stronger than other drop-in lockers. Due to its compact and simple design, the Spartan rivals more expensive lockers. Additionally, "drop-in" lockers provide affordable traction without the need of a professional installation. However, it is only recommended for lighter vehicles with 35" or smaller tires.

Toyota Positraction / Limited Slip Locker

Dura Grip Locker

The Dura Grip is a limited-slip locker that is aggressive yet uses an internal clutch that limits torque transfer to the tire with the most traction. This greatly reduces the chances of breaking an axle shaft or CV joint. It is made from forged 4320 steel and is 100% rebuildable, so you can change spring rates or repair normal wear without having to replace the entire unit. Limited-slip lockers are a safer option for on-road use, yet provide traction to get out of mild mud, sand, or snow.

Spool Locker

This is the Yukon Spool Locker. Yukon builds the strongest and longest lasting spool lockers we've ever seen. Made from high quality 4130 Chromoly steel, we firmly believe this is the strongest and longest lasting spool locker on the market today. The Yukon Spool Locker features a solid, one-piece construction that transfers 100% power to both tires at all times. This is a simple and inexpensive way to lock up your differential for maximum traction. Please note that we do not recommended spool lockers for on-road use. Please read the notes in the Spool Locker section above for more information.

Detroit Locker

The Detroit Locker is an automatic locker that replaces the entire carrier assembly. Made in the USA by Eaton, the history of the Detroit Locker can be traced back to 1941. Many of today's automatic lockers are based on it's time-proven principles. It has stood the test of time and can be found all across the globe. Many people consider the Detroit to be the end-all solution for automatic lockers, however it now has a serious challenger in the more advanced Grizzly Locker.

Truetrac Locker

The Truetrac is an automatic-type helical-gear style, limited-slip differential that maximizes wheel traction and enhances driving characteristics. Maintenance-free, it features smooth, automatic operation in forward and reverse. Its versatility makes Truetrac the ideal traction solution for almost any type of vehicle.

Lock Right Locker

The Lock Right Locker, like the Spartan, is an automatic "drop-in" locker. Over the years it has proved to be a reliable and inexpensive source of traction, however, like the Detroit, it is based on out dated technology. Regardless, the Lock Right has been used by our own employees with success. Drop-in lockers are easy to install and do not require professional assistance. The Lock Right is a good choice for light weight vehicles with tire sizes 35" and smaller.

Toyota Electric Locker

The Toyota Electric Locker is a selectable locker that replaces the entire third-member and may require axle housing modifications. Made by Toyota and offered on 1993 & newer model trucks, the "E-Locker" uses an electric motor and worm drive assembly to engage or disengage the locker via a shift fork and collar. It is a proprietary design that is not compatible with open differential components. Therefore we can only offer this locker fully assembled as shown in the picture. It is a reliable and popular choice and is offered in standard or high pinion configurations. Axle housing modification and custom wiring is required for trucks that were not originally equipped with an E-locker from the factory. Please click the image for more information.

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