Constant movement of the pressure regulator valve wears the valve body bore. Bore/valve wear causes erratic line pressure, resulting in delayed engagements, loss of lockup and high or low line pressure, depending on the area and extent of wear. Sonnax oversized pressure regulator valve kit 122892-03K restores hydraulic pressure control in Jatco/Nissan JF506E and VW/Audi 09A units.