I'm planning on changing the transmission fluid in my E420 and have it up on jack stands ready to go. I don't want to drain the fluid until I'm sure I know how to refill it.

Can someone tell me where I put the new fluid in? I don't see a place on the transmission itself. Is it in the engine bay?

I'm also having a hard time breaking the drain plug on the transmission pan loose, is it OK to just drop the pan with the fluid in it or will I make an unbelievably huge mess doing that?

Any help is appreciated!