Abstract: A grommet includes a hollow cylindrical body that is positionable in a bore hole of a transmission case and into which an oil fill tube can be advanced, to thereby establish a seal between the tube and case. The grommet defines an open top end, and a scored membrane is formed integrally with the body to cover the top end. Consequently, the grommet can be positioned in the bore hole to cover the bore hole prior to engaging the oil fill tube with the bore hole, thereby permitting pressure testing of the transmission case and preventing contaminants from entering the case. The oil fill tube can then be advanced through the membrane and into the bore hole.