mild clunking noise at idle from tranny area

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by jeffl0123, Apr 18, 2021.

  1. jeffl0123

    jeffl0123 Bobtail Member

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    Jan 18, 2018
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    Hey guys
    wondering what you guys thought. I have been hearing a not heavy but many mild clunking noise coming from the tranny area at idle. And yesterday while fueling up with truck idling, it was happening on a more regular basis. In the past maybe 1 or 2 times every minute but yesterday it was several times a minute at the last couple minutes of fueling up. I don't seem to notice it when I am driving. I have not tried to see if it dissappears when I depress the clutch but since I am going to do a PM on it today, I am going to try it. Could this be a Pilot or Throwout bearing? I was under the impression that a bad Pilot will make more towards a whine than a clunk. Let me know you thoughts. Also did not know if an output shaft bearing could also be a culprit but was doubting that.
     
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  3. AModelCat

    AModelCat Road Train Member

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    Most likely not a pilot bearing. It only turns when the clutch pedal is pushed in.
     
    bzinger and singlescrewshaker Thank this.
  4. jeffl0123

    jeffl0123 Bobtail Member

    35
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    Jan 18, 2018
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    Yep had my nephew come over and push the clutch in while idling while I was underneath and it made a hell of a noise when he depressed it so sounds like that is it.
     
  5. jason6541

    jason6541 Road Train Member

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    Try greasing throw out bearing(clutch release bearing) sounds like service intervals have been stretched and or it hasn’t been getting greased regularly
     
    baha Thanks this.
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