One other problem area that has not been discussed is one that I encountered with my 1995 Monaco Dynasty. We had a terrible odor when driving and none when sitting. I searched all the usual culprits, even removing the toilet and replacing the seal. I could not for the life of me figure out what was causing the odor until I got on the roof, removed the black water tank vent cover and looked into the hole with a flashlight, thinking perhaps that it was blocked. Much to my suprise I found that the vent pipe had broken at a joint about a foot below the roof line. Fortunatly I was able to re-attach the vent pipe and seal it with silicone. This solved my problem.