There's a new reference I hadn't heard before.
In reality I'm just one cog in the forum wheel that so many others also contribute to.

 

So after all my investigation (based on my lack of interest in tackling the rms job) I was out of the country for a bit so I delayed fixing it. But the rear main seal was not the issue after all this. It was the oil sending unit. Failed. Sending oil directly out of the motor. It was much cheaper and a whole lot easier to replace. The mystery oil leak and undercarriage oil painting has ceased dramaticIly. Haven't driven enough to fully confirm that it was the only issue. But sure was a huge issue. I'll keep ya posted.

 

Thanks for the update.

I found myself in a pretty similar situation. Thought I had a rear main leak. Turns out the valve cover gasket was leaking. Some of the bolts were actually loose enough to remove by hand. Went ahead and replaced the gaskets with a felpro set and cleaned the engine up while I was in there. No more oil drips on the trans bell housing for now.

Funny how we overlook the easier fixes...

 

Same here, and same conclusion. $20 for steel/rubber valve cover gasket set and my van is no longer leaking oil.