Dried out bearings, needs some lube. Usually clean with air gun or compressed air and then apply appropriate oiling, hand spinning the shaft during application to allow for the oil to work its way in before putting higher RPM strain on it.
As to your dump hose connection dripping, the rubber gaskets have likely dried out. Flush and clean the area, then rub vaseline on the gaskets and then open and shut a few times and recheck.
If they still leak, get a new valve replacement kit from Valterra and you can swap out the gate and gaskets at the same time.