The connection between the holding tank and the drain...

Years ago I noted a tiny black water drip and tracked it down to the connection I think your referring to - didn't take it apart (tank was full) but did tighten the hose clamp and the drip stopped. I would't be surprised if there was a rubber gasket at the end - but maybe not. Shouldn't be hard to test without gasket and see what happens. I have an older Fleetwood so maybe the same setup?