Positraction, Limited Slip, and Locking Differentials
Limited Slip Differentials
Positraction, Posi, and limited slip are all the same type of differential. Positraction is the name that General Motors chose for their limited slip design, and this name has been used over the years universally. Limited Slip differentials use a set of clutches or a helical cut gear set to apply power to both wheels when driving straight, yet allow for the wheels to turn at different rpms when needed around turns. These differentials are recommended for use with daily driven passenger vehicles and trucks. While the limited slip generally works well in ice, rain, mud, gravel, and snow, there are situations where a true mechanically locking differential is needed and a limited slip may not be the best choice.
Locking differentials (Lockers) offer a mechanical connection to drive both wheels in extreme situations. There are two different types of locking differentials.
- Automatic locking differentials are designed to drive both wheels 100% of the time, while still allowing for turns by unlocking. These are recommended only for serious off road usage and not on daily driven vehicles. These lockers do affect the handling of the vehicle, and generate a great deal of noise.
- Selectable locking differentials are designed to offer a 100% mechanical lock with the push of a button or other actuating device. These are excellent for dual purpose or daily driven vehicles. Selectable lockers operate as a standard differential when unlocked, so there are no affects to vehicle handling.
Here are a few videos to help explain: