flutter or vibration noise between 1300 and 1500 rpm

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by rwmoorh, Mar 27, 2009.

  1. rwmoorh

    rwmoorh New Member

    A couple of months back, my 2008 Silverado 1500, 4wd, 5.3L, extended cab started this vibration noise, when you lightly give it some gas between 1300 and 1500 RPM. I can't quite place where it is coming from, but it sounds like it might possibley be around the firewall. I went on line and read the GM tech bulletins and they mention the heat shield on the catalytic converters being loose on some of these truck and cause a fluttering sound, which, I guess, the sound I hear could be described as such. It's brief in nature and rather faint, and your really have to work at it to try and keep it going, like let off the gas and slowly give it more. I've tried various ways to get it to do it in the driveway, even having it in gear and turning the steering wheel to put more load on it, and I can't get it to do it.

    I had an appointment with the dealership, but they went under. Then a few weeks later the next closest went out of business. The dealership I've been buying from is 30 miles away and now it's getting a lot further to go, just to have somebody look at it. There have been 3 Chevy dealerships go under and rumor has it another may be on it's way also. I try to buy GM or Ford if I have to, because I feel that no matter how far I can go into the country there will probably be a dealership in every small town. Now they are disappearing in towns with good size populations, while the foreign dealers are still there. Now Ford, Dodge and Toyota are the closest for me. I like my truck and the gas mileage I'm getting, so I would rather stick with GM. I just hope one of these dealerships will re-open, but in this economy, I doubt it will be anytime soon.

    I was just wondering if anyone has had this problem with the heatshields and what it sounded like and if their symptons were like mine. If I ever get a dry warm day, that I don't have a dozen other things that need to be done, I will crawl under it and look, but in the mean time, it would ease my mind if anyone else has had the same problem and could confirm that's all it is.

  2. kcb37

    kcb37 Member

    Because of the nature of it, normally I would tell you to start it get under it and put your hand on the heat sheild should stop if it's the heat sheild. However in your case sounds like that's going to be hard to do. So what you can do, is use some wire and tie it tight to the cat. This will keep if from flopping around or banging on the cat. If it makes no noise then, it is the cat heat sheild.
  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    The best way to find the noise is to get your truck up on a lift where you can walk under it and listen while someone duplicates the noise from the driver's seat. Do you have a local garage that will let you use a lift?
  4. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    Does it only happen with the vehicle warm, or cold, or doesn't matter?

    Will the sound happen if you get on the freeway/highway and cruise at say 45mph so that your idle is in the "known flutter" zone? Or does this sound only happen at acceleration from a dead stop?

    I know you described some of the things you did to recreate it, but I didn't see if you said you put it in gear with your foot on the brake to hold the truck still while pressing the throttle.

    How fast are you going when you typically hear the sound?

    If you don't hear it on the highway at those rpm, then my guess is it's not really engine related, but speed related, and just coincidentally happens at those rpms.
  5. glmccready

    glmccready New Member

    Funny you should mention this! I just bought a 07 Silverado (28k) three days ago. I took it in Saturday because there is a vibration at 1200 MPs and 44 MPH. It also does it at about 35 MPH, and 1200 RPM but not as bad!
    So the mechanic went for a ride with me, and said he absolutely felt it too. Not in the steering, just in the floor and accelerator. At the shop he could feel it at stand still, in drive, foot on the brake, at 1200 RPM.
    Well in walks a mechanic I went to HS with, been there 25 yrs. He said.."yeh it's there and there is a Bulletin about it, exhaust vibration!! Saw one about 2 years ago, new truck".. There is a fix, get the dealer to look it up! If you have a problem let me know and I'll try an get the bulletin number.. It had to do with vibration from 900 to 1500 RPM
    So anyway the part that fixes it is something that attaches to the exhaust system, some "y" thingamabob.
    BTW: I have the 6 cylinder engine
    Good news is that it is not a major problem..just a resonance frequency! They ordered me the part and I hope that fixes it!

    UPDATE: Repaired and pleased, vibration is 99% gone!
    Last edited: Apr 20, 2009
  6. Dirtman

    Dirtman New Member

    rwmoorh hello I also have a 2009 Silverado 1500, 2wd, 5.3L, extended cab with exact same problems that you have describe with your truck. I have been all over and under my truck and I can not find where the noise is coming from. I just would like know if you ever found the problem.
  7. Dirtman

    Dirtman New Member

    2008 Silverado 1500, 4wd, 5.3L, extended cab

    Dirtman;123775]rwmoorh hello I also have a 2009 Silverado 1500, 2wd, 5.3L, extended cab with exact same problems that you have describe with your truck. I have been all over and under my truck and I can not find where the noise is coming from. I just would like know if you ever found the problem.
  8. Montana

    Montana Member

    This is a common problem with these trucks, even the older ones. I would have thought that they would have fixed it when they changed body styles. I have hte same issue in my '04 sub and have heard it once or twice in my new 'o6 Silverado. It's more of an annoiance than anything.
  9. Dan

    Dan Rockstar 100 Posts

    I HAVE been dealing with this for 33,000 miles and it still has not been found did the exaust fix and no change im out of warrenty in 3000 miles so it will either finaly break or be discovered after it has to be paid out my pocket

  10. heavy chevy

    heavy chevy Epic Member 5+ Years 500 Posts ROTM Winner

    I have a 08 and it does it also. It even did it the other day at idle. I dont know what it is It did it before the aftermarket exhaust and after. My 03 does it also. To me it sounds like my intake is vibrating or something. At first i thought it was the exhaust. I am gonna take it into the dealer on the weekend but they will prolly tell me the same thing they did on my 03. That the muffler piping before the cats need a flex pipe installed to decrease the vibration from the heatshields on the headers.

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