Early Slant 6 Rebuild

The oil pan is sealed tight. The leak is coming right at the bottom of where the engine and transmission meet.

As to why it’s started leaking in the past 2 weeks, no clue. I’ve been driving with this motor for about a year now. I had a ton of maintenance done when i first bought the car, which included new timing, new oil pump, new valve cover gasket and oil pan gasket, etc. And have had one tune up done and done another myself. But it’s not a very fun leak, I lost a quart of oil in ~2 weeks. Previously i went almost 2 months before i was noticeably down (not even a quart, maybe half a quart), And by then i was due for An oil change. But now it’s leaking like a sieve.

Then, I would pull up the timing for the engine rebuild and fix the rear main seal when the engine is redone.
That will save you the couple of hundred dollars that you will pay someone to just change out the rear seal and you stand a much better chance of the work being done correctly with the rear seal being changed with the engine out of chassis.