What is a "Lunchbox" Locker?
A "Lunchbox" locker (or drop-in locker) is a locker mechanism that is designed to fit into the stock differential carrier replacing the spider gear set and sometimes the side gears and pinion-shaft. The nickname "Lunchbox" comes from the idea of packing your lunch in a reusable "lunchbox" where you use the same "lunchbox" and pack in a different lunch. The stock carrier is the equivalent of the "lunchbox".
Lunchbox lockers come with advantages and disadvantages. An advantage that comes with these drop-in lockers are the fact that they are generally simple devices and are designed to fit into a stock open carrier or in some cases limited slip carrier, reusing stock parts. Since the ring gear is connected to the carrier and the carrier is reused, the ring and pinion gears generally do not need to be setup again. This makes it much easier for a backyard mechanic to install a drop-in "lunchbox" locker. It also allows the locker to be removed and the stock carrier parts be re-installed putting it back to an open carrier (or Limited Slip). Disadvantages of these types of lockers include the fact that their strength is limited to the carrier they are installed in, which can vary greatly. Their strength is moderate to less than moderate and for the most part support what seems to be up to a 33" tires and a mild amount of abuse before encountering problems and damage. Another disadvantage to a drop-in locker is that some have a more severe locking and unlocking feel over a full carrier locker. For this reason some drop-in locker manufacturers incorporate dampening mechanisms to reduce the backlash and harsh engagement / disengagement creating a smoother operating locker. For many people they are a good candidate for a first "economy" locker on vehicles that are mildly modified with slightly oversized tires.
Lunchbox Lockers operate in much the same manner as full carrier automatic lockers. These locker are automatic locking differentials designed to lock both wheels of the axle automatically with power input, when forward or reverse torque is applied, so that both wheels are providing 100% power to the wheels and creating essentially a "spool" that solidly connects the axle shafts together. When torque is not being applied, the locker is allowed to unlock, permitting a differentiation variance in wheel speed while negotiating turns. As an automatic locking differential, the primary drawback is their characteristics when they engage such as accelerating out of a turn or going from torque to no to torque to torque again such as when a manual transmission vehicle is shifting gears. In these situations, the driver must be aware of the characteristics that will affect the handling of the vehicle. For example during a turn the inside axle will spin slower than the outside axle, which is the basic purpose of the differential. If torque is applied to an automatic locker during the turn it will engage due to the torque engaging the locker gears. When the locker engages, it will cause the vehicle to push towards straight ahead or possibly to the inside of the turn. The net effect is somewhat un-predicable handling characteristics when compared to open differentials. These effects are much more noticeable in shorter wheelbase vehicles and smaller lighter vehicles. The odd handling characteristics will also be more apparent if road traction is compromised such as in rain or when the road surface is ice or snow covered. Further noticeable characteristics of automatic lockers can be a banging or clunking noise during engagement of disengagement, delayed engagement, and added significant backlash, also known as slop, in the driveline. Disengagement can be abrupt and sometimes a ratcheting noise can be heard when cornering. Most people who use automatic lockers become accustom to these handling characteristics and adjust their driving style accordingly to accommodate it or just simply just get used to it.
Here's a few examples of "lunchbox" lockers on the market:
Here's a photo of a typical "lunchbox" locker:
A "Lunchbox" locker (or drop-in locker) is a locker mechanism that is designed to fit into the stock differential carrier replacing the spider gear set and sometimes the side gears and pinion-shaft. The nickname "Lunchbox" comes from the idea of packing your lunch in a reusable "lunchbox" where you use the same "lunchbox" and pack in a different lunch. The stock carrier is the equivalent of the "lunchbox".
Lunchbox lockers come with advantages and disadvantages. An advantage that comes with these drop-in lockers are the fact that they are generally simple devices and are designed to fit into a stock open carrier or in some cases limited slip carrier, reusing stock parts. Since the ring gear is connected to the carrier and the carrier is reused, the ring and pinion gears generally do not need to be setup again. This makes it much easier for a backyard mechanic to install a drop-in "lunchbox" locker. It also allows the locker to be removed and the stock carrier parts be re-installed putting it back to an open carrier (or Limited Slip). Disadvantages of these types of lockers include the fact that their strength is limited to the carrier they are installed in, which can vary greatly. Their strength is moderate to less than moderate and for the most part support what seems to be up to a 33" tires and a mild amount of abuse before encountering problems and damage. Another disadvantage to a drop-in locker is that some have a more severe locking and unlocking feel over a full carrier locker. For this reason some drop-in locker manufacturers incorporate dampening mechanisms to reduce the backlash and harsh engagement / disengagement creating a smoother operating locker. For many people they are a good candidate for a first "economy" locker on vehicles that are mildly modified with slightly oversized tires.
Lunchbox Lockers operate in much the same manner as full carrier automatic lockers. These locker are automatic locking differentials designed to lock both wheels of the axle automatically with power input, when forward or reverse torque is applied, so that both wheels are providing 100% power to the wheels and creating essentially a "spool" that solidly connects the axle shafts together. When torque is not being applied, the locker is allowed to unlock, permitting a differentiation variance in wheel speed while negotiating turns. As an automatic locking differential, the primary drawback is their characteristics when they engage such as accelerating out of a turn or going from torque to no to torque to torque again such as when a manual transmission vehicle is shifting gears. In these situations, the driver must be aware of the characteristics that will affect the handling of the vehicle. For example during a turn the inside axle will spin slower than the outside axle, which is the basic purpose of the differential. If torque is applied to an automatic locker during the turn it will engage due to the torque engaging the locker gears. When the locker engages, it will cause the vehicle to push towards straight ahead or possibly to the inside of the turn. The net effect is somewhat un-predicable handling characteristics when compared to open differentials. These effects are much more noticeable in shorter wheelbase vehicles and smaller lighter vehicles. The odd handling characteristics will also be more apparent if road traction is compromised such as in rain or when the road surface is ice or snow covered. Further noticeable characteristics of automatic lockers can be a banging or clunking noise during engagement of disengagement, delayed engagement, and added significant backlash, also known as slop, in the driveline. Disengagement can be abrupt and sometimes a ratcheting noise can be heard when cornering. Most people who use automatic lockers become accustom to these handling characteristics and adjust their driving style accordingly to accommodate it or just simply just get used to it.
Here's a few examples of "lunchbox" lockers on the market:
- Lockright Locker
- Detroit EZ Locker
- Aussie Locker
Here's a photo of a typical "lunchbox" locker:
