Planetary differential

Planetary differentials distribute torque differently between the two output shafts.

They are used, for example, to split power between the front and rear of an all-wheel drive vehicle when torque dominance is required on one of the two axles.

Some cars have devices that lock the differential (completely or up to a certain limit) so that a wheel with good grip can push the car, even if the other wheel is on an extremely slippery surface.