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Intermittent grinding noise front left

32K views 20 replies 6 participants last post by  country1911 
#1 ·
Hey everyone, I have an issue with my 2002 Z71 5.3 extended cab that is causing me to beat my head against the wall. I have had this truck for 3 years and have yet to come across something I could not diagnose with a Google search and some common sense.

What it is doing is at 15mph to approximately 40mph it starts to make a grinding noise coming from the front left of the truck. The thing is, once the truck is warm, it stops making this noise. It almost sounds like a power steering pump but louder. Could it be a sticky caliper? Although the wheel never smokes or seems warm after driving. I have read about wheel bearing and hub assemblies and they seem to be a common problem with these trucks. I jacked up the front and the wheel has a slight movement from left to right(hands at 3 and 9) but not up and down.

I try to not be a parts replacer and actually diagnose what's going on. With that said, I do have new shocks on order as the old ones are shot and in need of replacing.

I really need help here guys. Let me know if you need any more info.
 
#4 ·
Just had to replace the whole hub assembly on my truck. Same thing, griding noise... eventually it locked up enough that it wasn't safe to drive.
I have a 91 Chevy, so I am not going to say it is the same... but I had bad bearings but had to replace the whole hub assembly. Because mine was so old and never done, I had to replace rotor, and also had to put new ball joints on because I had to remove them in order to remove hub.
 
#6 ·
I had my mechanic replace the hub on my left front last winter, too. I believe the general idea is to remove the tire, rotor, and brake assembly, and then pop the hub off, and put the new one on. Sounds doable... let us know how it goes.
 
#7 ·
Is there any way to verify this is the issue? Is it the motion side to side that means it is the hub? I have replaced hubs on my dads Ram before and the instructions look very similar, just need to look up some torque settings.

When I replace my shocks tomorrow I will inspect the hub and breaks closely.

Oh, and the truck has 255k so it is probably due for something to go wrong. Truck has been great so far, really no major issues.
 
#8 ·
I watched my mechanic test the hub- he lifted the truck up, and then grabbed the wheel. He rocked it up and down, and it moved. Side-to-side, it's going to move anyway, since the steering components will allow the wheel to move. That's my advice- see if it rocks in an up and down motion- which it shouldn't, if the hub is OK.
 
#10 ·
rocking the tire up and down will check your upper and lower ball joints. jack it and see how hard it is to the move the tire. I had a 98 with the old 88-98 body style. a wheel bearing went out of it might have taken 30 minutes to change. just make sure you have one big socket to fit the axle
 
#12 ·
Haha yeah, I guess I just assumed I had to jack it up. I am planning on doing this tomorrow as long as my shocks come in.

I did some minor looking today at work and it seems my idler pulley has some play in it. Like I can wiggle the pulley back and forth, although with the truck running it it straight(no noise either tho). I have read that this may cause this noise also. I may replace that and the tensioner pulley as I have no idea the last time they were changed and I have had the truck for a while now.
 
#13 ·
Update: I replaced all 4 shocks today. While I had the truck off the ground I took the opportunity to check the wheel bearings. They were absolutely solid when trying to move them 12 to 6. Like so solid I had to double check the truck was off the ground.

So I am at a loss here. I would like to explore the pulley option a little more as I had the oscillating grinding noise while sitting still today. For the 15 bucks I may just replace the idler pulley that wiggles.

I should add that this noise comes about 10 seconds after cold startup and is non existant after about 5 minutes.
 
#14 ·
thatsi will check your ball joints when pushing at 12 & 6. pusing at 3 & 9 will check wheel bearings, but if your having the noise sitting still i have no diea does it still do the noise in 4 wheel drive?
 
#15 ·
in park your getting the noise? or were you at a stop light? is it usually at lower rpm or when your dumping more fuel into the engine? could be a water pump, could be all kinds of stuff. give us a detailed description on what its doing this might help pin point the problem. is it running warmer? any fluids? everything you can tell us, the more detailed the better.
 
#16 ·
Well, it was down about a half inch of coolant a few days ago, filled that up. Never runs over 205 tho and hasn't been low on coolant in the 4 years I have owned it. I was in reverse, stopped in my driveway when it did it earlier. It does it for 3-4 seconds then goes away. And like I said, it only happens intermittently for the first 5 minutes of driving. Once everything is warmed up, it goes away. It generally only happens while driving and at slower speeds. I am unable to reproduce it sitting in the driveway, but I may not be putting any strain on the right parts.

I do have some play in my wheel when pushed/pulled at 3 and 6 but this may be steering as it moves the other wheel as well. Even with the other side on the ground, both wheels still move slightly(<1/4").

I also noticed today that the inside of my rotors are not getting even wear. The outside is even all the way across, but the inside has 2 wear strips an inch apart. This is on both front wheels.

I am on my 3rd drivers window regulator tho, learned the hard way that 40 dollar parts from ebay don't last over a couple years. Replaced it with a good unit this time tho.

I can't really think of anything else, but if I do, I will post it up.
 
#17 ·
Update: I loosened the serpentine belt and spun all that would spin and the idler pulley(the one that wiggles) makes a grinding noise. This may or may not be related to the previously mentioned noise but for 10 bucks at the local autozone, I will be picking one up regardless. I will keep this updated for more progress
 
#20 ·
Well good news, bad news time... Good news, I have narrowed it down. Bad news I think it is just plain old piston slap. Maybe that's good news, I'm not sure. I removed the serpentine belts and started the engine and still noise. I had my wife help me and shift the truck into reverse. I was able to pinpoint the sound to the passenger side of the engine and then I got a shorter but similar sound on the drivers side. When I was able to get close to it, it sounds more of a rattle and after watching some YouTube vids of piston slap, it is pretty close.

I replaced the a/c belt while it was off. I think at this point I am going to drive it and not worry too much about it. The rattle only occurs on cold starts and goes away within a few minutes.
 
#21 ·
Time for an update: this problem has been getting steadily worse and I had pretty much resigned myself to replacing the motor when it finally went.

So yesterday I am under the truck painting the frame and such, prior to winter when I bump the heatshield on my drivers side converter... Rattle rattle rattle. Crap. All this worry and stress and it turns out the heat shield on my cheap replacement cats has broken its welds and is rattling all over the place. So I pull it off and this morning the sound was gone.

My stock cats had no heat shield so I am debating on having this welded back on it not. It is the upper shield between the body and the exhaust. I may just use some worm clamps to hold it on until I can decide.
 
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