It is a common misconception that 4x4 and traction go hand in hand. The truth is that most 4x4 vehicles send power to the wheels with the least amount of traction once difficult terrain is encountered. The problem is simple – when one of your vehicle’s wheels loses traction, your highway minded factory differential directs all of your vehicle’s power to those spinning wheels. On road, the standard differential allows each of your wheels to turn independently thus eliminating any binding during turns. Off road, this becomes a major burden as engine power will take the path of least resistance, which occurs at the wheels with little or no traction.

Newer vehicles with limited slip differentials (LSDs)j or positractions may offer some improvement over standard differentials, but more often you’ll find the slipping is not "limited" enough to maintain forward progress. Automatic locking differentials also will address this situation, although they have their disadvantages. In addition to being noisy, automatic locking differentials often upset the on highway and off road driving characteristics of your 4x4. During normal driving conditions, vehicle responsiveness becomes less predictable, and when highway surfaces become wet or icy, the driver must use extreme caution just to keep the truck in control. Dual or Multipurpose vehicles truly need a selectable locker such as an ARB air locking differential to take advantage of their on and offroad ability and manners.

~Scott
www.axleboy.com