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

All-
Hey.. Since I know a lot of you are far more mechanically inclined than I am.. Wanted to throw this out there. Recently, I've noticed a pretty pronounced Grinding, Whirring sound coming from the front end of my Silverado when in 4WD. I only engage the 4WD when on snow/ice pack or rain.

Recently these things have all been changed:
Brand New Hub Assemblies in Front
New Calipers up Front
New Brake Pads up front.

It seems the sound is coming from my driver front at the moment, but I've also heard it previously on the Passenger Front as well.
I was hoping the hub change would have fixed it- but no luck. Today riding down the road it sounded horrible.

Any advice?
Thanks!!

Grinding could be the differential. Could be u joints too. If you put it in 4wd and when you take off you hear like clicks or snaps that could mean the gears in the differential are ate up. Whiring noise tho could be u joints. Grease the u joint and then check your differential fluid.

Since it only does it in 4wd narrow it down to your 4wd components. Check them and then just use process of elimination.

More than likely the CV Joint gone bad.....not that you'll replace it yourself, but this describes it quite explicitly.

YouTube Flick

Cv joint is when you make turns. Turn right and if your hear the click it means the left one is bad. And vise versa.

Quote:

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Originally Posted by Yunkman

More than likely the CV Joint gone bad.....not that you'll replace it yourself, but this describes it quite explicitly.

YouTube Flick

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Yeah if im not mistaken your chev has an independent front suspension. My truck has a solid axle. Mine has u joints, yours will have CV shafts. CV shafts will snap and pop amd make grinding sounds. But id definately get it checked out by a mechanic asap. Its real tough to diagnose things like this when you cant see em.

Quote:

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Originally Posted by Bryson

Cv joint is when you make turns. Turn right and if your hear the click it means the left one is bad. And vise versa.

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Just goin thru my notes from school last month, you are correct that they will make noise on turns, but they can also make noise and vibrate going in a straight line. Noisy Usually on acceleration. Although it would be louder and more noticable when turning.

Also check the pinion bearing. Look for leaks at the pinion seal. We just replaced a front diff from a 2003 chev, make sure the 4x4 actuator is fully engaging. This one we replaced wasnt and the fluid was full of chunks of alum. (If its electronic 4wd)

Drive backwards & turn hard (use a car park) left or right, thats when the CV's really make a noise.

bearings also make more noise in turns, but so does bad rubber on worn tires
I'd suggest checking out a Chevy truck 4X4 forum for clues/answers

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

just a guess here but probably something in the front differential I doubt it is the cv joints since on a Silverado they turn all the time but there is no torque on them in 2wd it could possibly be in the front drive shaft or in the transfer case but you would probably hear/feel that under your feet more then from the front end. if you can get all 4 wheel off the ground and get someone to put it in 4wd and accelerate you can use a mechanics stethoscope and listen to the components and narrow it down

of course if you have a chevy built before 1988 you have a solid front axle and you could have axle bearings or wheel ujoints going out

Thanks guys for all your replies. Here are a few answers to questions. Maybe this helps you help me possibly?

2000 Silverado
As Soon as I push button into Auto 4wd or 4WD High. I get the sound as soon as I start moving as well as going down the road.
It is Only in 4wd, not hearing a sound or feeling anything in 2WD.

Any other questions. Please feel free to ask.. I don't want to tear up the truck.. but with the weather outside- I'm in my 4wd all the time.

I'd look towards the gearbox, have you checked the fluids in it? Might be a good time to change it. Let the first quart go into a clear plastic qt jar or something, then comb through it for metal bits, maybe just let it settle then pour it off the top till you get down to the bottom so you can know if anythings breaking loose. Also poke your finger up on there if possible to check for anything loose that didn't come out with the oil.
After that I'd look on downstream till you find it

Also wanted to add: No Click or Pop in turning. This whirring and grinding is straight down the road, wheel straight- you still get the whirring and grinding if going into a turn.. but no "popping" or "Clicking" if I am turning the wheels.

So As I said.. I'm really not too mechanically inclined.. where do you check the differential fluid? I've never seen like a "dipstick" under the hood for it. Should I be looking for a transfer case "plug" like an oil plug under the truck? If I do find said plug and drain it- where do I add in new fluid. You all are getting to see the "super green" side of me.

Ok.. Did a quick search. Will look into this:
https://www.youtube.com/watch?v=yzBiqB_zqhY

Quote:

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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

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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.

So is the consensus that I have a bad bearing within the front differential?
Does that mean the front differential will have to be dropped and torn apart?

The front differential is sorta like a rear diff. There's a fill plug on it somewhere. With a rear diff you just pop the cover off to drain, but the front ones I'm not sure how alike they are(mine has to be pulled, or you can use a pump to pull the oil out thru the fill hole)

The transfer case should have a drain, and a fill plug.
Do you have a repair manual for that vehicle ?

Let a local shade tree mechanic, a friend or neighbor with some mechanical abilities help you detect the problem. Hope it doesn't happen to you like it did to me.....my GMC kept acting up until it died on the road, but then nobody could find the problem and still haven't. It's still dead. Whatever it is will get worse until it ruins something else like a rear or frontend housing, transfer case or wherever the problem exists and then you'll be walking.

You've already changed the hubs and that should have included new wheel bearings in the front if they did it right. That should eliminate that source and leave you to suspect the front differential, the CV joint shafts or the transfer case itself (doubtful on that). A lift on a hoist and inspection should help to pinpoint the problem. I had a 99 GMC halfton 4x4 with a growl that we never did detect. Traded it off. Let us know the outcome.