Well that's good to hear it's not a massive job (like home toilet). I think I'm going to do it just for piece of mind. I'll be on full hookups for a month starting tuesday, so I'll flush everything out and use one of those stink killer additives before I open the mouth of hell.
@j-d: mine does indeed have that overflow... that's what I was referring to smelling up close. I believe it has a trap inside and it has water in it and I can't detect a smell coming from that hole.
@garyemunson: I did pull the air valve off and inspect, and as you say - a 02' trailer's gray tank smells like death itself once that valve is off. The smell was not the same as my lingering odor though - so I really think it's the black. The valve really looked to be in fine condition, and the kitchen one is certainly fine. If this doesn't work, I'm sure they are cheap though and I'll try one anyway.
