Pressure Regulator Valve

The pressure regulator valve controls line pressure to provide the correct pressure to apply clutches, supply lube and apply TCC. The valve exhausts line pressure to the lube or converter clutch apply circuit to reduce line pressure to a required operating pressure. If operating conditions require a higher pressure, as in high load, the regulator will exhaust less and line pressure will increase.

The pressure regulator contains the pressure regulator valve, line pressure control plunger, and pressure regulator spring which are the main components that control line pressure.

On initial start up the pressure regulator is bottomed in the bore by spring and line pressure control pressure. At this time no pressure is being exhausted until orificed line pressure increases enough to cause the regulator valve to move against spring pressure. As the regulator valve moves against spring pressure line pressure is exhausted to lube and converter clutch apply to control pressure.

At the same time that line pressure begins to act against spring pressure, line pressure control from the line actuator is applied to the line pressure control plunger to increase force on the regulator valve in the same direction as the spring. Line pressure is increased as pressure to the pressure control plunger is increased by the line actuator.

When engine rpm is raised and lowered the regulator valve and control plunger float back and forth against spring pressure and line pressure control as a single unit. As rpm begins to rise, pump output increases. The resulting line pressure increase acting on the pressure regulator valve forces the valve against spring and line pressure control to the point where line pressure is exhausted. Line pressure drops and the spring and line pressure control force the valve back, clocking off exhaust. During normal operation the valve continually maintains line pressure by moving back and forth to exhaust.