While working on my new SeeLevel sensor install, I noticed that Winnebago used 3" Neoprene fittings to connect the grey and black tanks to the ABS drain lines. My neoprene fittings are cracked, in many places, and the black fitting is leaking. I will need to pull apart the entire ABS drain line to replace these neoprene fittings.
I hope to replace the originals with the type that are wrapped in stainless steel. These will offer some protection from the weather and road debris.
My rig is a 2019, just 3 years old. I suggest checking yours. The original fittings are doomed to fail.