A helical gear differential is a mechanical unit that, unlike the Locker, offers smooth and progressive power transfer. If one tire begins to slip relative to the other tire, a separating force is created between the pinion gears and side gears. This generates internal friction which slows the spinning wheel and sends power to the wheel with the most traction. These differentials are comparable to the strength of a Locker, but without it’s downsides. The Strange 9” S-Trac, due to materials and design, exceed the strength limits of the Locker while offering all the benefits of a helical gear unit.