More food for thought. I have a 2012 Winnebago Raven with 2 grey and 1 black tank. After 2 years kitchen grey would not close 100% so hooking up at campsite would give you a bit of mess when you remove the cap. Brought it in for service and they lubed up the cable and all was good. Two months ago same thing, same tank. Brought it back. Had to drop the underbelly cover and replace the valve. Cause was sloppy manufacturing. In the assembly of the unit they had drilled out the drain hole for the tank and let the resulting donut fall into the tank. It got partially lodged in the open valve at some point causing distortion and deterioration of the seal requiring the valve to be replaced. Bill had higher labor hours on it for this than the primary reason I had brought the unit in for which was a failed slide motor(slide motor failed because wife kept on trying to retract slide without making sure obstacles were clear. Multiple attempts caused a shift in square resulting in greater load)
