Strange Rubbing Noise in My Silverado

Did you wobble or shake the wheel while it was off the floor before undoing it all the way off? Any slack in the wheel bearings or the steering mechanism would have revealed itself then. If there is no rubbing sound when the wheel is spun off the floor and no noise from the brakes then I would suspect the track rod ends in the first instance. If they are all right and the front axle is driven then suspect the constant velocity joints. Do it both sides. If there is a rub when the wheel spins then suspect the wheel bearings or something that shouldn't be there lodged in the brake mechanism; in my case it was a tiny piece of stone that I flicked out with a small flat screwdriver.

Is there a statutory annual inspection regime in force in your part of the world? What is on its last report? Did it pass the inspection the last time?

Sounds like a bad bearing, but also check any rubber boots for breakage between the transfer case and wheel.

Before beginning to toss money at mystery problems though, I've found that it's worth getting an estimate from a reputable shop or dealership...even if it costs some money for the diagnosis.

I'll let them figure out what's going on, then fix it myself.

put a go-Pro cam in the wheel well report back to us

Bearing or maybe a CV joint. Also check your brake pads and be sure nothing is dragging.

Does it "rub" when turning both directions?

How do your brake pads and disc look?

Finally, if you haven't already, jack the tire off the ground and grab it at 6 and 12 o'clock and try to move it in and out. It should not move.

Next, put some one way tension on it (push in at top, pull out at bottom) in those positions and spin the tire. Do you hear the noise then?

If you find nothing by doing this, take it to the man.

the wife says she hears it in both directions, but I only hear it on right turns.

You wife is right. Maybe drive the car once with out her sitting on that side!

Look inside your front left fender for a stowaway Chevy Cavalier. It's rubbing on the tire when you turn.

Usually they hole up there at night when they didn't make it back to the junkyard in time for lights-out.

If you only hear it in a turn it is most likely the CV joint.

Only on turns? And you did not mention the noise when braking. I believe the differential in the transfer case may not be allowing the two drive-shafts to move at different speeds on turns.

If there is a limited slip did in the front axle, it could be that also.

If you have jacked up the front, and do not feel any lost motion moving the tire up, down, left or right, try removing the front drive-shaft, and putting the transfer case in 4 wheel drive high range. Drive the truck and check for noise. If it is gone, change the oil in the transfer case with recommended type and then exercise the system by driving in figure 8s on and off the gas. This will force the internal clutch packs to load and unload. That will force that new fluid between the clutch plates of the diff.

If the scuffing is still there, wet the ground under the front tires and turn the wheels hard to left or right and see if the problem goes away. If so it may be the front locking diff. Same procedure as for the transfer case. Good luck.

Did I mention that the rubbing sound started only in aggressive turns? That means when in a tight turn in a slow speed, no rubbing sound. In a wide curve at a high speed, no rubbing sound. But when the wife drove she put the truck in the tight turn as fast as she could and when the weight of the front was applied to the axle, the rub was pronounced. Over time, it got worse and worse, so now I just baby the truck around the curves to avoid the rubbing.

I have a dangerous idea to try out. Go where there is no traffic and with a flat bladed screwdriver, move the pads away from the discs on the front of the car. Both sides.

Make sure that the master cylinder does not overflow....as you will be pushing brake fluid back, or loosen the bleed screw and catch the excess in a can....

The do the tight circle driving, but not touching the brakes and see if it still rubs....this may tell you something or not!!!.

If the car is an automatic, you may need brake pressure to shift into drive, so you will need to put on the park brake, start the car with the foot on the footbrake, then select drive, before moving the pads away. Be careful!!

Another possible check is to jack a front wheel off the ground, move the pads away from the disk and then grasp the tyre at the top and bottom and see if there is any bearing play. There should be none at all....

You are also testing the suspension by doing this, so if there is movement, make sure it is not wear orientated in the suspension....

I had a rubbing noise in the front of my 2004 Silverado, and took it everywhere for various checks and spent quite a lot of money on it. It gradually got worse and then it felt like the tire would change steering on tight turns at low speed. Nothing could be found wrong with the front end. One day on a trip, I jacked up the rear end for another reason and was checking the tires for damage after a bad road. When I tried to rotate one tire with the other on the ground, it would not rotate. The lockup rear end had seized and the tires would not rotate speparately. It worked fine with the rear end cold, but not hot. The noise in my front end, turned out to be the tires slipping on the pavement due to the locked rear end. Once I realized this, I could hear much more noise coming from the rear end when I walked beside the vehicle than ever came from the front end, but I heard the closer noise more from the drivers seat. I don't know the history of my current rear end because it came from a junk yard. My original rear end failed on a trip when a bolt fell out of the cover and it was run dry for some miles. I am still driving it around town but avoiding "heating it up" on the road. It works OK around town

Good solid infos that the OP should check up on.

Can he unlock "hubs" on this car if he wishes...? That might "fix" the problem, which would point to "axle windup" as you appear to have had....

Also, he (the OP) should check the wheel bearings on all axles as this can, in severe cases, bring a "rubbing" sound simply from the brake pads when turning....but I have the feeling that you are nearer the mark than I am!!!

Some wheel bearings can be adjusted, some can only be replaced....

Unless it's aftermarket, GM does not offer a front locking or limited slip differential on 4 WD pickups.

I liked manual hubs because you could lock them in and stay in 2WD. (no locking diff in front) Then, when needed, you could shift into 4WD "on the fly".

My automatic locking hubs required you to stop and shift into 4WD.

I only have to stop to put it into low range 4wd- high I can do on the fly.

You missed my point. The problem was in the rear, but caused sounds in the front as the tires were forced to slip sideways on the pavement. Almost all the rear differentials in GM are locking, which are far better than limited slip, at least in the west where we have mud, clay, sand, and snow.

As us Ford owners say about our vehicles, Don't worry about it until it stops making that noise!

I am hearing a few terms thrown around here, and would like to toss some thoughts out there. A differential is designed to allow the two wheels on the rear axle to cover different distances. Weather it is because of a curve, or two different sized tires.

The issue with that is that when traction is limited because of rain, ice, snow or loose soil conditions, or because the available power to the tire is more than the one tire can transmit, we want both of the tires to transmit power to the ground. For this we need to have some way to make both tires spin at the same speed. This is usually a device that can lock both of the wheel gears that turn the axle shafts together. It may be a spring loaded clutch, spring loaded sprocket, or an air, electric, or mechanical device that will lock the two wheel gears. And with this assortment of systems comes a different name for each manufacturer. Protraction, Detroit Locker, No-Spin are some of the names used by different manufactures. Limited slip, is usually a generic term for any of these devices that will allow both tires to transmit power to the ground.

When we deal with a "4 wheel drive" vehicle, we used to have a simple sliding gear in the transfer case that would lock the front and rear drive shafts together. This was good when you were on loose ground, but horrible on dry hard pavement. Because if there was any difference between the ground traveled by the front tires compared to the rear tires, one tire had to slip. In driving, this felt like a brake would be applied, and then released over and over again, especially on turns. To make these systems more user friendly, transfer cases became equipped with a differential in them. This system would then send power to either the front axle, or the rear axle, whichever was driving the vehicle the shortest distance. To permit power to be sent to both axles, there was an ability to bypass the transfer case differential, and lock both drive-shafts together when needed. This combined with some sort of limited slip rear axle is what most "4 wheel drive-all or wheel drive" vehicles have. Serious off roaders may have a limited slip differential installed in the front, but not a common thing. These LSDs have a high wear issue with tires, and hurt gas mileage considerably. For that reason, I do not think it is an option from the factories.

There is one other device that warrants a mention here. There is a differential that has no locking device to it, but still drives both wheel gears, while allowing the tires to turn at different speeds on turns. The Thorson design differential relies on the principles of screw and worm gears to provide seemingly perfect function as a limited slip differential.

Now back to the OP. If his vehicle has a differential that uses spring loaded clutches to drive both rear wheels, and the vehicle has been driven in such a manor as to have not forced those clutches apart sufficiently to allow the rear end grease to keep the clutch plates from sticking, he could get the symptoms he describes.

Most of your explanation is OK, but some points are not well explained or you yourself misunderstood maybe, I cannot say which. Fine but important details....

You mix up a "locked" differential with a "Limited Slip" differential which may in some cases be the same hardware unit possibly, but under two different circumstances. You need to be fully aware of that and the differences.

I have underlined the questionable unqualified sentences, I think I know what you meant to say, but you didn't and for someone with less knowledge than you, it could be misleading..

You said:- The issue with that is that when traction is limited because of rain, ice, snow or loose soil conditions, or because the available power to the tire is more than the one tire can transmit, we want both of the tires to transmit power to the ground. For this we need to have some way to make both tires spin at the same speed.

What you could have said was that power will be divided to each wheel, at the percentage of designed slip. A concept that many simply do not understand.

A fairly common one is 60:40 or even 70:30, so when one wheel spins, the other one gets either 30 or 40 percent of engine power/speed, depending upon the design. The spinning one gets either 60 or 70 percent....

LSD (not the Beatles one!) is usually defined (in the car manual at least) with a percentage of "slip". The reason is, if you have a normal Diff and one wheel is in say a slippery hole, all the engine power goes to simply spinning that wheel, but not to getting the car out of that hole using the other(s). Not good for a vehicle designed for "Offroading" for example.

For a normal road car with LSD, its usually only winter time that brings ice or snow under one wheel, with different "grip" surfaces (usually only two wheels) and the LSD then allows both to be driven to some designed degree. A winter Godsend...Whereby a LSD will still supply a percentage of the engine power to the other wheel(s), allowing it to (hopefully) pull itself out of that hole, using the tyre(s) with the better grip.

By the way, unless a diff was designed to drive different sized wheels, there may be massive wear on the bearings inside the Diff and its lifespan may be severely curtailed....usually not to be recommended to have different sized wheels on 4 wheel drive and never ever on any car even with one driven axle to have two different sized wheels on that axle. Even worn and new tyres can affect the diff if on the same axle...... The front to rear Diff may handle it better.....

Any percentage of slip up to locked, will still wear the tyres more than having a normal diff(s), but most people will accept that as a small price to pay.

Though I, as a Landrover driver of many years ago, I then liked the switchable "Lock" that allowed me to decide when I wanted 2 or 4 wheel drive, with no center diff even present, 50:50 front to rear. Some modern things nowadays take too much away from the driver I find, but thats just me I guess.....I would gues that LSD had not been implemented by Landrover then!!

A trick that sometimes helps cars with a normal Diff and a spinning wheel is to partially apply the handbrake (assuming that the driven wheels and the handbrake wheel are the same ones, not always true). Or "stutter" your foot on the foot brake.

But many cars nowadays have ESP or similar, which drives the ABS to do this for you by braking the spinning wheel. GREAT!!

My car has the Mitsubishi equivalent of that and gets me out of "holes" with no LSD for example.....great when pulling a heavy trailer over wet grass for example using summer tyres.

Have a great day Bob C.

"You mix up a "locked" differential with a "Limited Slip" differential which may in some cases be the same hardware unit possibly, but under two different circumstances"

Not true.

A locked differential LOCKS both rear axles together 100%. That's why they have a centrifugal mechanism that completely UNLOCKS the axles over about 20 MPH. Above that speed no amount of axle speed mismatch will cause the diff to LOCK or engage in any way. I know, I had one in a Chevy K 10 PU.

A limited slip diff uses a clutch pack to transfer power to the slower axle, but does not mechanically lock the axles together.

Limited-slip differential - Wikipedia, the free encyclopedia

Locking differential

I agree completely, but I wanted to cover all cases as its many years since I had anything to do with such things and it might have been that some car manufacturer had managed to include both since then!!

I try never to say "never".....

Lyn, you covered the difference in principle between a locking and limited slip differential but the Z80 by Eaton which is what the Chevrolet and GM is equipped with behaves differently from other locking rear ends. It takes about 1 turn of a rear wheel to automatically lock up mechanically. It is termed a "low speed locking differential" and is like no other. They do have problems, as all mechanical devices do, but not as many as limited slip unit I have had in the past. This video shows the difference, but driving it in bad conditions shows it better.

Eaton Z80 in Silverado

That's what I thought I was explaining, but using the term "locked differential" instead of "locking differential" may have mislead you and others.

One of the 4WD vehicles I owned came from the factory with the G-80 locker. It was a great option and I never had a problem

I'm not aware of a Z-80 locker made by Eaton or anyone else.

The Detroit locker is the only other mechanical locker I know of and it IS locked all the time, but has a provision to allow one wheel to out run the other one for cornering. Never liked them, myself.

Please see the Eaton site for an explanation of all of the types offered, along with some names.

http://www.eaton.com/Eaton/ProductsServices/Vehicle/Differentials/index.htm

The link is truly great. I never realised just how many there were nowadays, and it was as well and good that I was cautious about saying that there might be LSDs that could also lock the axle completely, THERE ARE!!!

Someone criticised me for that, I forget who, I will look in a moment!!

Just looked!

It was Lyn being even more "Picky" than I could ever be......!!!!

HEY Lyn, read the link from Bob C, it seems what I said was true when I was being cautious and not even sure!!!

Here is the link again for you:-

http://www.eaton.com/Eaton/ProductsServices/Vehicle/Differentials/index.htm

Many thanks Bob C!! You have proved my comments in post #25 with this link that Lyn did not like......

Lyn, remember my comment? It was:-

"You mix up a "locked" differential with a "Limited Slip" differential which may in some cases be the same hardware unit possibly, but under two different circumstances"

You said in you post #28:- "Not true."

Well they have!!! and it IS TRUE!!! Both can be in the same piece of hardware.....

DUUUHHHHHHHH!!!!

Thanks to Bob C.

Congratulations.

You have simply reinforced the notion that even a blind hog finds an occasional acorn.

Only a Pig would know that!!!!

Which is probably why I didn't!!

"even a blind hog finds an occasional acorn."

WTF! That was uncalled for! I may be a bit over weight, but with my glasses on I can still see the middle line on the eye chart.

LOL!!

Eaton is the manufacturer of the Z80 used by GM.

I thought that was what I had said. Must have been too much LSD. Thanks.

Not lately has Andy Germany said so little with so much.

I understood what you said. We must be on the same trip.

Well done, you surprise me!

LOL!!!

Here's an off-the-wall possibility: Check your plastic fender liners to see if they are loose. I have a 2002 Suburban and my front left one has been banged up by snow pack, mud, rocks and all matter of abuse over 215K miles. I know mine is beginning to flap in the 'breeze'. You might find rub marks on the plastic liners if you go looking for it. The tires are not as likely to show the wear.

Good luck with your quest.

Now we're getting closer, especially since OP only mentioned that he heard the noise, not that he felt it in the steering wheel. I had a very similar experience with my Jeep, noise started on hard turns in one direction but not the other, suspected everything mentioned above, then realized that I didn't feel it in the wheel.

Crawled underneath and found a heat shield above a nearby exhaust pipe/muffler had worked loose and was rubbing on the drive shaft. Turn one way and the centrifugal force moved it closer to the shaft, turned the other and it moved away. Put your vehicle in the air and inspect for loose parts and the resulting rub marks.

WOW! I had almost the exact same thing happen to me. Except that in my case it was the transmission mount that broke, and it was the drive-shaft that was grinding away on the floorboard on very hard left turns at Freeport's 1/4 mile asphalt track. Its like Deja Vu all over again.