Help

[snowman44]

I have a 2008 chevy silverado 4 wd with only 78k on it. Over the past week as I am accelerating I hear a noise coming from underneath the cab almost directly under me. The noise is quite loud. Does anyone have any suggestions on what it could be? The noise does not occur every time but quite frequently. Thanks for the help in advance.

[rjgti]

transfer case half shaft maybe

[00Silverado4x4]

What kind of noise? Humming, thumping, banging, clanging. Need more information, if not a sound clip would be helpful.

[snowman44]

id say more of a grinding. Today barely heard it. yesterday wouldnt stop and sounds awful

[00Silverado4x4]

Easiest thing to check would be hub bearing and brakes. If a hub bearing goes it'll make some grinding type noise and possibly result in abnormal brake wear if it's bad enough. I've been through the hub bearing issue with both my current and previous truck and it's not a pleasant sound in the least.

[snowman44]

I noticed a pattern this morning where It sounds like it mostly makes the noise when dropping down a gear and then as accelerating will start to go away.

[snowman44]

Took to my friends and everything underneath looks good. We bent one of the hangers so exhaust pipe is not rubbing on mudflap. The noise is still there. I noticed the other day when I had a load of wood on the truck I never heard the noise. I need to find out the problem and hope it is not major.

[Brendan Cosworth]

I'd have a transmission shop look at it. Could be a specific cog based on your downshift description

[snowman44]

Now it is making the sound when idling too so I am thinking not transmission.