Peterbilt 379 vibrating .need help !please

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Nestor, Apr 4, 2018.

  1. Nestor

    Nestor Light Load Member

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    I have a Peterbilt 379 short hood 1997 is that a low air leaf ? And yes I feel it on my seat . Don’t feel nothing on the steering wheel
     
  2. Nestor

    Nestor Light Load Member

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    So I took off both drive lines from tranny to first differential . I changed u joints but I just threw drive line back on . I didn’t mArk it before I took it off . How do I check my u joins are line up ?
     
  3. Nestor

    Nestor Light Load Member

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    I don’t feel it in the front or steering wheel
     
  4. Goodysnap

    Goodysnap Road Train Member

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    Provide vin and we can tell you for sure but is most likely is low air leaf. This is type of vibration is most often an issue in the driveline.

    Was the vibration present before the u joint changes? Or only after. Your best bet if its outta phase and or outta balance is to remove both pieces and have them balanced and reinstall. I have chased phasing issues before and often the fastest route is to just rebalance the whole thing. Always mark yokes and sections before removal and put them back the same during servicing.
     
  5. greaseburner

    greaseburner Light Load Member

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    drive shaft.jpg
     
    Clunk and Nestor Thank this.
  6. swaan

    swaan Road Train Member

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    Screenshot_20180406-094941_Google.jpg

    This will give you an idea. It has to be in phase . You do this with the splines on your slip joint
     
    Clunk Thanks this.
  7. blueblack

    blueblack Bobtail Member

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    I am kinda new here but the wearing out of ur tires could be the tires causing the vibration. An alignment and fresh tires of course will help. I had a problem, same thing, in neutral and around 50km/h , vibrating light that. Good day