Strange Camping World offers the replacement valve themselves.
https://www.campingworld.com/72quot%...B&gclsrc=aw.ds
But I doubt a new valve is needed. What is needed a an external gate valve on the outlet pipe. There is always residual "stuff" in the plumbing lines. Unless you jack up the front to drain the front tanks and lines completely, then jack the rear so as to do the same to the rear gally tank, there will be "stuff" left. Adding the gate valve stops the surprises when you remove the cap.
Buy Valterra 3" RV Waste Dump Gate Valve w/Cap t from here or wherever. https://www.amazon.com/Valterra-Wast.../dp/B076FG17DZ
