Torsen

From Freepedia

The Torsen limited slip differential was invented by American Vernon Gleasman and manufactured by the Gleason Corporation. Torsen is a contraction of torque sensing.

The Torsen uses crossed axis helical gears to increase internal friction when one wheel spins faster than the other. The slower-moving wheel always receives more torque than the faster-moving wheel. The Torsen does not have a preload so some traction is necessary in order to transfer torque. If one wheel were raised in the air, the Torsen would act like an open differential and no torque would be transferred to the other wheel.

One of the most famous uses of the Torsen LSD is in the various Audi Quattro models. It is also used for example in the Toyota Soarer (or Lexus SC430)