Front End Vibration
So I noticed a rhythmic vibration coming from my front end for the past 2weeks or so. I decided to do some testing on the way home from work tonight. At about 55mph, you can barely hear/feel the vibration. Between 60 - 69mph it gets worse. At just over 70, it's hardly just noticeable. It's there weather or not the engine is under a load, I turned the radio all the way down and had the heat on low just to rule those out. Once I cruised down to 50 - 55mph it disappears again. I've searched on here quite a bit and I've seen people mention that it could be the drive shaft out of balance. I'm 99% sure it's not a low tire or unbalanced wheel. Seeing how the truck is a 2009 with 2600 miles, I'm just not sure what the heck it could be! I'm planning on taking it to the stealership since it's under warranty, but I had to vent and solicit ideas. Any ideas or none at all will be entertained!
Truck info: 2009 4.0 4x4 Fx4