Jersy, Have you talked with the contractor that installed the roof? They should be able to answer your questions easier then someone who has nver seen the house. I have never heard groaning as a result of a ridge vent, but from what you wrote, it has something to do with air movement. Do you know if you have soffitt vents as well? If not, that could be the problem. Sorry I can't answer you question, but check back as there are some pretty clever folks that hang out on the site.