It might surprise you that your leaky rear main seal is actually a leaking oil pressure sending unit over by the Distributor. Leaking down to the pan seam and down like a leaky rear main.
always worth a look because those are a known culprit!
a miserable job (i mean, not nearly as bad as a rear main, but still) so plan on lots of brake clean and rags. it's even more fun if somebody has plumbed in the pick up for an aftermarket pressure gauge!