OK, this conversation has caused some additional brain activity so I went out and gave another look to my sewer compartment. Now, this is a 2017 Axis 25.2. There is a round opening in the bottom of the sewer compartment that is about 4 inches across. It is threaded as if something should be there. The sewer line is turned down just barely above that opening and ain't gonna budge. I gave it a close look and tried to turn it up. No way. So, am I missing something? If so I'll give Thor a call..
This thread has warmed the heart of an old sewer worker.
Especially the video. Be still my heart!