Abstract: A direct replacement boost valve assembly for use in combination with a pressure regulator valve within the valve body of an automatic transmission is disclosed. The boost valve assembly functions to boost line pressure during high load conditions in response to torque signal fluid pressure, which is proportional to engine torque. The present boost valve assembly is comprised of hard-anodized aluminum valve pistons, which are disposed within a wear resistant aluminum sleeve for maximum service longevity. Annular lubrication grooves formed in the valve pistons which comprise the boost valve assembly retain a lubricating film of transmission fluid to center the valve pistons within the sleeve ensuring accurate operation and reducing mechanical wear. The present valve sleeve features a fluid inlet port system, which increases the delivery of torque signal fluid pressure to the boost valve in order to restore its function to original factory boost ratios and specifications.

Abstract: A replacement 1-2 shift valve for an automatic transmission, which restores a smooth shift from first to second gear thereby correcting a shudder shift or a complete failure to shift from first to second gear is disclosed. The present 1-2 shift valve comprises a valve piston including at least one bi-directionally tapered valve stem that changes the direction of transmission fluid flow within the valve such that a rebound force is generated which acts to propel the valve piston in an axial direction toward the second gear position of the valve. The piston lands which comprise the valve piston are provided with a plurality of annular grooves that function to retain transmission fluid and to center the valve piston in its mating bore to resist to side loading during operation. In addition, the present valve piston is provided with an anodized surface finish, which increases service longevity.