Stench under the bathroom cabinet

[TucsonJim]

We've noticed that there is a horrid smell coming from the cabinet under the bathroom sink. I checked for leaks and could find none. Everything was dry. I examined the trap and the plumbing all the way into the basement and it was intact. When I tried to trace the vent line up to the roof, I found that the vent line is terminated with an air admittance valve instead of an exterior vent line. The air admittance valve appears to have failed and holding tank gasses are venting into the cabinet which makes the whole rig STINK! We put a lot of gray water deodorant in the tank, but the whole trailer still stinks.

I tried to remove the AAV, but it appears to be glued in place. Is this the case, or can I unthread it? If not, I'll have to cut it out and replace it which will be much more involved. We're hitting the road in the morning and getting a little nervous about ongoing problems.

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Adding Key words:
Smell, sink, odor, valve, grey, gray