Tractive Differentials. A differential is a device, usually but not necessarily employing gears, capable of transmitting torque and rotation through three shafts, almost always used in one of two ways. In one way, it receives one input and provides two outputs; this is found in most automobiles. In the other way, it combines two inputs to create an output that is the sum, difference, or average, of the inputs.

Apart from the differential offered for the SD90 gearbox, which is the Tractive origin design, based on development work Tractive did in 1995 — 1999, Tractive offers the differentials for many other brands. The Tractive differential has proved to offer winning performance. This is top class performance at a reasonable price! Tractive produces clutch pack differentials with 3 internally toothed friction discs per side. The diff features floating ramp plates for immediate response without the need for preload. The ramp plates always have two sets of ramps, for example 30/65 or 40/65 degrees for drive and overrun respectively. The internally toothed discs are molybdenum-coated and the external discs are nitrided for increased longevity. The bevel gear dimensions are dimensioned to give long life and smooth operation. For long lifetime on ramps and gears, four planetary gears are used, running on high strength crossed shafts.