loud intermittent scraping noise

Discussion in 'General Chevy & GM Tech Questions' started by kennyb79, Jun 25, 2012.

  1. kennyb79

    kennyb79 Rockstar 100 Posts

    so two nights ago, coming home from the firehouse at 2:30am my suburban starts making a weird LOUD scraping noise. at first I thought my muffler was dragging...then it stopped. then started again, lasted about 8-10 seconds each time and stopped. all in all for about a 1 mile stretch it did it on and off about 8 times. completely random, a few seconds ata time then stopped. I pulled over and couldn't find anything, and drove home about 4 miles and it didn't make a sound.

    so yesterday the same thing, and tonight the same thing. just a random scraping noise, loud, then stops then starts again. then I could go for miles without hearing it again. There is no change to the way the suburban runs, it doesn't pull to one side or the other, or shimmy or shake,,,just makes this noise. tonight I thought it was done for because the sound lasted for about 15 seconds before it stopped. tranny fluid, and oil level looke good. I did have some issues with the 4 wheel drive not engaging (light flashing) last winter, but I also changed all the fluids last winter, I did engage and disengage the 4 wheel drive in my driveway when I got home and all seemed fine. my son was with me, we both think the sound is coming from the center of the vehicle between us. I've never heard a transfer case go, but it does have 190,000 on it and it usually runs like a top.

    any help or experience would be appreciated
  2. sstoner911

    sstoner911 Epic Member 5+ Years 1000 Posts

    I would check under it for any loose plastics - lower air dam, plastic wheel well covers etc...I would think a Burb is high enough to notice those things easily. Maybe you ran over something like a traffic cone?

    Kinda grasping at straws here really :)
  3. rileyjr16

    rileyjr16 Epic Member 5+ Years 1000 Posts

    Was it when you were accelerating in any way? Like a hard acceleration or even a normal one?
  4. nancygrl

    nancygrl New Member

    Our '97 Silverado does something similar. It seems to only make the noise when going up a hill and while accelerating. Have no idea what it might be since it doesn't happen all the time.
  5. kennyb79

    kennyb79 Rockstar 100 Posts

    Actually the first time it happened I thought my muffler was dragging, I backed off the gas and when it stopped the burb wasn’t any louder, then it did it again and again. My speed wasn’t any more than 40 at the time, and I wasn’t accelerating. By the time I got to a spot where I could pull over and check it out, it had stopped and started quite a few times.

    usually I’ve been at a constant speed, not accelerating. And it’s shifted thru the gears just fine. I did look underneath and around it and didn’t find anything out of the ordinary. Its completely random, just driving easy down the road, it starts making the noise and then stops just as quick. No vibrations, no wheel pull, no change in the vehicles behavior at all while it’s making the noise or after. It sounds just like I ran over something or something is dragging, then it stops.

    Today after work, I’m gonna pull the front tires, check the brakes. I’m thinking maybe it’s a dust shield rubbing against the wheel, or even the outside of the muffler against the driveshaft my big fear was something expensive like tranny or transfer case, but its so random and metallic sounding that that doesn’t make sense. My next fear was that it would lock up a wheel and I’d go into on-coming traffic and hit a semi…but it doesn’t seem to affect the steering or make it pull to one side or vibrate. Maybe I should just turn up the radio…
  6. dragging pipe sound

    dragging pipe sound New Member

    I had a similar sound coming from my 1995 Mitsubishi Montero. At first it sounded like a dragging tail pipe or other hollow metallic pipe but more intermittent than if it was constantly dragging (ding ting ting...silence...ting ting ting ding ding...ting--that sort of thing). I checked under the vehicle and nothing was dragging. The sound happened whether I drove 65mph or 25mph and didn't change with engine rpms, breaking, or acceleration. I found that the rattling occurred when I revved the engine while parked as well, so I had a friend rev the engine while I took a look under the vehicle and found that the sound was coming from a loose dust cover around the yoke and universal joint of the drive shaft.

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