In a Hypoid type axle the teeth on the crown wheel and pinion simultaneously rotate and slide against one another, putting high pressure on the faces of the teeth. This action requires the use of extreme pressure (EP), and other, additives to the oil to prevent wear and micro-pitting of the gear surfaces. This hypoid oil is blended to GL5 specification used in many cars and light chassis vehicles from 1960 onwards. Replaces oils originally specified as EP80.