I don't see where you mention the front cover seal or the harmonic balancer seal surface. From your description, both of those are suspects. And it sounds like you have a substantial leak! The gasket behind the engine mount/front cover plate can only be replaced after removing the front plate. The screws are staked in place when the engine is assembled, so that operation is seldom done. A part of that gasket seals the front main cap to the front plate, so if that portion is missing, that might be the source of your leak. If that portion of the gasket is missing, you can fabricate a new one out of thin gasket paper, or use RTV as others have suggested. But you have to take off the front main bearing cap (and oil pan) to do that. If you use RTV, take care not to plug the drain holes in the front plate.
Another possibility is that the two cap screws (bolts) that hold the front cover to the front main cap are missing or loose. The bolts pass through the front main cap into a threaded reinforcement on the front cover. You should be able to see the bolt tips at the bottom of the front cover if you take off the harmonic balancer. You might be able to feel with a paper clip, without removing the harmonic balancer, to see if those bolts are in place, but that won't tell you if they are tight.
Hope this helps.
Harvester
