Shift High To Low - Phase 2

Fig 1: Shifting High To Low - Phase 2

Courtesy of CHRYSLER LLC

The stepper motor (2) first moves to the right which causes the ratio valve (3) to vent oil from the primary movable pulley at a speed that allows some belt clamping to be maintained. As the oil is exhausted, the moveable side of the primary pulley moves to the left allowing the belt to be pulled down into the low ratio position by the constantly maintained line pressure in the secondary pulley. As the primary pulley moveable side moves to the left, the ratio valve is pulled to the left which closes off the oil venting from the primary pulley thereby stopping the ratio change. For each position of the stepper motor, there is a corresponding position of the primary moveable sheave therefore.