Strange Thrumming at 65 MPH +

I have a 2008 that I just bought with 25K miles on it. At 65-70 MPH I hear a vibration or thrumming coming from the front of the vehicle. Nothing is felt just heard. It is equipped with the long front mudguards. Could that be what I am hearing?

 

Is thrumming a word?

 

is your truck lifted?

 

No my truck is not lifted. No mods at all except running boards which are secure. It has these very long flexable mud guards on it that I suspect are causing this. I guess I could take them off and see what happens.

 

any vibration felt through the steering wheel? I would check the steering rack and make sure the wheels are properly balanced.

 

First thing I'd do is rotate the tires, front to back in an X pattern. That moves the fronts to the rears and reverses direction. Drive the truck and listen if the sound has moved, went away, etc. I have a Toyota camry with Michleins that I do not rotate often enuf, when done there is road noise for 5K before it goes way. You said nothing about vibrations thru the steering wheel or seat so I'd say if it is tires, it is directional wear, not balance. By doing this you have eliminated the wheels and tires from the problem, or if the sound moves with the rotation you know you have a tire/wheel problem.

 

08' with 25k on it....good find!