How to find location of oil leak

[51Deluxe]

My 51 has had a substantial oil leak since I got it, even with the engine reportedly being rebuilt. I've alway assumed it was a rear main seal leak since it is dripping off the back of the pan. Just occurred to me today that oil from the rear main would usually drip from the bellhousing (Hydramatic in this case). Correct? What other oil leak sources would drip from the rear of the pan, besides the pan gasket?

[joefrazer]

Your rear main seal is leaking. The pan has a lip on it that extends into the bell housing's inspection cover. Oil is running off it and down the outside of the pan. My 50K does the same thing...although its drip is minor enough, for now.

An easy way to tell is to clean the lower half of the engine and then run it to see if oil is leaking from the pan gasket, oil sending switch, or the front main seal.

[retired wrench]

Spray the engine down with degreaser then late at night when no one is around take it to the car wash and wash it down.