Recently my truck has been making a very loud noise coming from the front end. I was driving to work one day when I heard a noise that sounded like a think piece of metal was flapping underneath the truck somewhere. Thought it might be the dust cover so I took it off and the noise persisted. The flapping noise got worse and turned into a clunking/popping noise. Noise sounded like it was coming from the front passengers side so I changed the cv axle, but the noise persists. Noise does not seem to occur when the truck is in neutral and rolling, but as soon as you put it into gear it begins to make the popping noise. The noise happens when you go forwards or backwards and seems to get a little quieter when 4x4 is engaged. Wheel hub seemed to be fine. Cant figure this one out so any help would be greatly appreciated.