I have a 2007 VW Jetta 2.5 sedan with automatic transmission. When I'm driving, at around 35/40mph I can hear a loud hum. It sounds like it's coming from the driver's side front. It gets louder and louder and then gets quieter around 70. It's pretty loud and really annoying. I've seen that it could be a bad wheel bearing, but I just wanted to check to see if it could possibly be something else before I go out and buy a new wheel bearing. Any tips on changing a wheel bearing? Thanks!