It has been awhile since I have drained the fluid and changed the filter on the A413 / A670 3 speed automatic transaxle. I believe the gasket you mention seals the filter to the input port on the valve body. I never removed the screws and attached this gasket to the valve body. Just allow the filter to press the gasket material around the screw heads. The gasket material should compress sufficiently around the screw heads and allow the filter to seat fully. I seem to remember that the filter is held in place with 2 torx head screws???