Abstract: A gasket which is interposed between a pair of valve bodies of an automatic transmission each of which is provided with a hydraulic circuit for feeding operating fluid to frictional engaging elements of the automatic transmission. The gasket which is interposed between the pair of valve bodies is formed with a slit which in turn communicates with a fluid passage which in turn intercommunicate the hydraulic circuits of the pair of valve bodies, and has a valving element defined in the gasket by the slit. A portion on the side of the hydraulic circuit of one valve body is provided with a valve seat over which overlies and closes the slit. Depending upon the difference in pressure between the hydraulic circuits of the pair of valve bodies, the valving element elastically deforms itself so as to permit the flow of the operating fluid from one hydraulic circuit into the other hydraulic circuit.