I have an 2008 3295rk (I have had it about 3 weeks) there is a leak I think from the black tank...! No smell..but dirty blackish water.
Haven't pulled the underbelly off yet. But there is a smaller plumbing pipe than the largest that then T's into the larger 3" drain pipes. If this is to the black tank, why the smaller pipe for black and the larger for the grey? Can someone identify what this pipe is? Does anyone know if black tank drains from the bottom of the tank or on the side?
Would this be a vent pipe to roof?
And my cap is leaking?
Looking at your floor plan looks like that pipe is from the washer hookups. Not uncommon
for the washer drain to go direct into main drain (3"). I see that the toilet is as so on the other side of the wall and the black tank is there. Black tank is most likely the problem and just leaking through the opening for the smaller drain. Unfortunately only real way to tell is drop the chloroplast, I had a leak on my 07' Montana that ran about 6 feet on top of the chloroplast before it came out. Good luck.