Liquid waste knife valve leaking (not the black tank)

I use the twist on valves because I don't like surprises either but the valves are usually easy to replace, as long as you can get to it. Only 4 screws and nuts and 2013 shouldn't have any rust. Just rinse and drain it good and hold your breath. It only takes a few minutes.

BTW, the last valve I had to replace had a damaged slide where something was in the valve when it was closed. Oil wouldn't have helped.