Manual Transmission Shift Shaft Seal by National®. Width: 0.187″. Inside Diameter: 0.625″. Outside Diameter: 0.945″. Housing Bore: 0.937″. Don’t just repair a leak, prevent future problems with a National Oil Seal. This part is manufactured using exclusive National Dynamic Edge technology that generates a dynamic pumping action to keep harmful contaminants such as dirt, moisture, etc. out of the seal and other wheel-end components.