So on my 06 I recently noticed that on the highway once I hit 60 mph exactly I start to hear (more so feel in the throttle and floorboards) a slight humm. Kinda zzzz...zzzz...zzzz type deal. I'm puzzled. It's nothing major. In fact to someone that doesn't drive my truck all time time they probably wouldn't even notice it.

I thought maybe my 4 wheel drive was still engaged but I put it in and took it out and even backed up afterwards but it still does it.

Any thoughts?

 

Nobody has a clue as to what it could be???

 

You might check your front u-joints or your wheel/hub bearings.

 

Mine is doing exactly the same thing...everything I have read thus far makes me think it's u-joints going out. To your point, it was driving me crazy the other day going down the hwy...turned off the radio (windows up) and asked the wife, "you hear that humming?"...
Typical response..."all I can hear are the tires and your loud @ss exhaust!". Obviously, no help there
Let me know if you diagnose it before me. I'm gonna have to let it ride for a bit before any more $$ goes towards the truck!

 

Same thing here, to date I have spent $900.00 for driveline balance front and rear, new front yoke, all new u joints, two in the rear were bound up. Not included in that is new tires and a different set of wheels with all that it changed the vibration from 62 mph to 73 mph which helps for daily driving, the one thing I noticed was when the front driveline was removed the vibration was the least of all changes, but was still there. so it must be either in the front differential or transfer case. I have learned to ignore it as I have read that all the diesels have different vibration and I must say that up to 73 mph it is the smoothest truck I have driven. I have no history on the truck as I bought it used at 127,000 and believe it was used off road quite a bit and abused. Hopefully this list will be added to and we may get to the bottom, for now that I know I'm not going to chuck a driveline so I'm going to live with it.