As soon a practical, replace the valve. It failed once, it will do it again.
My experience with mechanical things (close to 50 years) says it will fail completely when you are most in need of it operating properly: Trying to dump tanks in the rain with 3 others waiting to use the station comes to mind.
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!