First of all, I'm not very mechanically inclined and I have a problem/question...I have a 2006 4X4 Silverado with just over 20,000 miles. When I get between 65 and 80 I can hear/feel a intermitent hum in the front end.

Ive taken it to two different GMC authorized shops and both hear the noise; one says its the tires, though they've been rotated. The other says they can't identify the problem so they won't do anything to fix it.

Both have checked the oil and theres no metal, the only problem I have is when I engage the AUTO 4WD the noise disapears, so I'm thinking its not the tires?

Does anyone have any idea of what I can tell the shop when I take it back? My warranty expires in a few months and I'd like the problem fixed before it comes out of my pocket. Is it the tires?

Any advice or suggestions would be great.

Thanks

 

while you had it in 4wd did you reach the speeds of 65-80 mph.It sounds to me like the tires(front) are cupped,you get huming and slight vibration and certain speeds.i had cuped tires on a s10 and it did it at low speeds.family member had a tarus and its cupped tires made huming between 50-55.does factory warrenty cover tires.if not i would rotate fronts to back and see if the noise moves to the rear.another way is drag hand across the outside tread by sidewall and if it feels like every other lug is raised then there cupped.but not always noticable that way.

 

I've rotated the tires and the noise persists. I'm trying to find another set to try them out to see if theres a difference.

I have engaged the AUTO 4WD at 70mph and the noise disapeared, and when I went back to 2high the noise came back........

THanks for the input

 

i'm guessing you rotated the tire+rim, but if you rotated only the tires, it could be a bent rim. engaging 4wd changes the resonance characteristics. it changes other things too, but ...

 

engaging 4wd at 70mph did nothing at all.....if you do some reading you will find that after about 30-40 mph the 4wd kicks out.....sounds like a diff or t case problem maybe even a wheel bearing on a long shot

 

maybe that is the problem right there ... OP found engaging 4wd at 70 did _something_ so maybe the auto-kick-out is not, errr, kicking out.

 

Some of thats over my head...but tires and rims were rotated at the same time. Thanks for the input.

 

I vote front diff pinion bearings... Maybe a U-joint, but I would expect more of a vibration than a hum from U-joints.