Leaking Pan

I'm sure it's the pan. (famous last words...)
It's a Turbohydro 400 in my Chevy-chassis step van, that I use for my business. Being in a step van, it gives me plenty of room to see. I've cleaned everything several times in order to see the leak. Above the pan stays dry.
I always use white grease on gaskets, it has always worked nicely- helps the seal and makes them easy to remove. Copper coat's a good idea. I might even have some.