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2011 3500hd rattle at 30-35mph

Discussion in 'Chevy Trucks' started by dlcs, Nov 3, 2012.

  1. dlcs

    dlcs 2000 Club Member
    Messages: 2,149

    My 2011 3500hd makes a rattle noise sometimes when your going 30mph and step on the accelerator. Sometimes you can barely hear thios rattle at low speeds or under a load like pulling at trailer. The truck only has 21,000 on the odometer. Could this be the transmission? Today while pulling up to a stop light, the truck down shifted really quick. Whenever I take it to the dealer, the truck never makes the rattle noise. I hate this, any suggestions?
     
  2. Cosmic Charlie

    Cosmic Charlie Senior Member
    Messages: 228

    My 2011 HD 2500 does it also, just when under very light acceleration at 30 mph - never any other time

    I think it's pinging, be it slightly, my truck has 48,000 miles and has done it off and on since new ...

    Try premium gas, I haven't because I'm not worried about it - I think these engines have knock sensors (that advance the timing) and that is just one spot (in rpm & trans gear) that isn't perfect.

    The down shift thing is normal - mine will do that once in a great while also - its just not as smooth as the old 4 speed automatics - these trans are fully computerized - you will also notice that when they down shift when your gradually slowing down the computer bumps up the rpms a hair to smooth it out ... but not perfect all the time ..

    At least thats my belief ...
     
  3. dlcs

    dlcs 2000 Club Member
    Messages: 2,149

    Would the pinging be more prevelant when pulling a trailer up a hill? I'm think your right about the pinging, going to try a higher octane gas today and see if it helps. Thanks!
     
  4. Cosmic Charlie

    Cosmic Charlie Senior Member
    Messages: 228

    There are 2 knock sensors - one for each bank

    I have never had a code show so I'm guessing all is good ... for me anyway ... so far