How many of us are there? Owners of Dodge based RV's?

Hello, New here but already learning lots. 1978 Dodge B300 360 engine 20' Leisure-Craft 51,000 miles. We just bought this last fall and very happy with it. Everything works and the engine runs great. Only problem is rear main seal leaking, about a quart every 100 miles. Is there a easier way to fix this, without pulling the engine apart?

Thanks