Hi guys, my first post here. I have a 2002 Outback Limited. I bought it two months ago with 145k miles on it. I've recently noticed there was a clicking noise when I drove a few days ago. Usually happens when I go over 15mph, but it stops when I brake. Today, I found that the clicking elevated to a slapping sound, like something was hitting the car. The noise seems to get faster as I drive faster. Any ideas what this could be? Thanks!