I have an oil leak coming from the rear of my engine. I am assuming it is the rear seal. I cleaned the engine and the valve cover and rest of the engine is dry but the bell housing is wet with oil. It only loses about 1 quart of oil every 3,000 miles. I took it to a mechanic and he told that replacing the rear seal might not work due to the 204,000 miles on the engine. He said the a new seal may not fit well enough because of wear. Is this a possibility?