Installed my lower unit today after a reseal ..shift rod missed the hole and pushed the seal/plug up and to the side. I cannot figure out how to reinstall this thing. ..I see no groove etc that it would fit in. It's a 2" heavy rubber washer with a hole and slit. I assume it fits into the engine lower cover? Carbs are off, 1990 E150STLESB. Thanks for the input