Need help on my Silverado.. Grinding.. Whirring sound up front in 4WD

You can also put it up on jackstands and let it idle in gear, walk around it listening for the sounds, just don't get under it or be in its way if a jackstand lets loose

My guess from the sounds of it, would be a bearing within the front differential.
On the basis that I'm asuming that it is IFS and that you mention that the sounds are in 4wd, ...and not in 2WD, ...here I am asuming this as well.
I had to have a bearing replaced in the front diff. of my '03 Sierra a few years back, ...had a nasty whirring/groan sound while in 4wd and sounded normal in 2wd.
I doubt it's the CV shafts, if the noise changes from 2wd to 4wd as they are always spinning anyway

Originally Posted by Jvcr1

My guess from the sounds of it, would be a bearing within the front differential.
On the basis that I'm asuming that it is IFS and that you mention that the sounds are in 4wd, ...and not in 2WD, ...here I am asuming this as well.
I had to have a bearing replaced in the front diff. of my '03 Sierra a few years back, ...had a nasty whirring/groan sound while in 4wd and sounded normal in 2wd.
I doubt it's the CV shafts, if the noise changes from 2wd to 4wd as they are always spinning anyway

Sounds right from here (NZ) a floating shaft with a bad bearing won't make much noise, but put pressure on it & the shaft will go out of centre & nek minute theres a % of your HP going into spreading two of the ball bearings apart & sideways pressure on the bearing housing & cage.
Maybe the squealings from a ripped up bearing cage? Or the gears grinding at each other.

I know from practice that if a wheel bearings starting to go bad, do a looooonnnngggg turn to the right, or left, while travelling strait. That puts pressure on the bearings & makes them louder.
Also, running the bad bearings wheel on a continous painted line on the road will quieten it down a bit. Painted road is smoother.