when i sit in my car i can hear a knock coming from my back passenger side wheel well. It sounds like someone is tapping on my wheel well while i am driving. It only happens when i am going about 10 mph. when i go faster it goes away or when i am breaking it goes away. i pretty much have to be coasting (still in Drive) to hear a knock. i checked to make sure nothing was stuck back there, and i thought maybe a wheel bearing but people said thats like a grind or a howl. so i am guessing thats not it. hopefully i can jack it up and look at it soon. Thanks in advance guys and any help would be Greatly appreciated!