It is likely the correct fix yes, and the replacement cable actuated waste valve you need is the LaSalle Bristol Cable-Actuated RV Waste Valve for Black Water Tank - Spigot to Hub - 36" Cable # 34466N4AB36GM, 48" Cable # 34466N4AB48GMA, or 72" Cable # 34466N4AB72GMA.
To install it use LaSalle Bristol ABS Solvent Cement # 3447530889. view full answer...
I would be happy to help you and I have a couple of options for you depending on the dimensions of your recessed ball. The first option and the one I would strongly recommend is the Demco Recon Gooseneck-to-5th Wheel Trailer Hitch Adapter for Recessed Ball item # DM8550046 will fit a recessed ball mount if the ball sits no lower than 13/16" from the top of the bed. It has a gross towing weight of 21,000 lbs and a vertical load limit of 5,250 lbs.
The other option is the Ranch Hitch Universal... view full answer...