Trans leak from small metal cylinder

That's the park cable housing. That cable going into it is the park cable that engages park when you move the park lever into the park position. The park housing has a gasket where it mounts to the tail housing and the park cable also has an O- ring on it. It's one or the other or both that's leaking. Did I say park enough times? lol
No, you didn’t say park it and fix it while it’s park.