Whirring noise when accelerating

[qcarey]

Good Morning everyone, first time posting here and hoping to get some input on an issue that has been taking place on my 2008 Tahoe LTZ 2WD.'

When I am driving in excess of 35 MPH and tap the gas pedal, I hear whirring noise coming from under the vehicle. The noise is fairly light but has been getting worse.

The noise only takes places when I press the accelerator, it goes away a second or so after I left off the gas, and seems to been worse if I am accelerating up slight inclines on the freeway. I cannot get the noise to occur when the gas is not being pressed and I cannot get the noise to occur when I am not in excess of 35 MPH.

The first shop told me it was a rear wheel bearing, replaced those, no luck. The second shop said it was a pinion bearing, purchased a bearing kit and had all the bearings replaced in the rear differential with no luck.

Does anyone have any insight as to what may be causing this aside from a pinion bearing or a wheel bearing? I have searched other threads and all the answers point at those two items, but after having them replaced, it is obvious they are not the culprit.

Any help is appreciated.

Thanks

 

[dmad1]

I think your mechanics have led you astray. Check under the hood for frayed belts, air cleaner not seated, vacuum leak. Maybe even an exhaust leak. Try it without the AC on and maybe turn off the heater. Look for play in the fan coupler.