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"klunking sound"

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rh88k5, Nov 4, 2002.

  1. rh88k5

    rh88k5 Registered Member

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    \"klunking sound\"

    my blazer has been making a noise kinda like a klunk or thud when I come to a stop or start to accelerate. its not ujoints, I know I have a little slop in the rear, but I think it might be my drums hanging up,then releasing, is that possible? or should I look elsewhere? anyone have any ideas? TIA Rich /forums/images/graemlins/k5.gif
     
  2. mattyblazer

    mattyblazer 1/2 ton status

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    Re: \"klunking sound\"

    I get a thump, thump, thump when I accelerate hard, I feel it through the floor of my 87'

    Matt
     
  3. 88k5blaza

    88k5blaza Registered Member

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    Re: \"klunking sound\"

    i know when mine slows down and downshifts into second it clunks and its my rearend
     
  4. BigBluOx

    BigBluOx 1/2 ton status

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    Re: \"klunking sound\"

    This is also a documented (by GM) sound coming from the front driveline. Make sure the sliding portion is lubed (they even sell a special grease for it, but regular grease eliminated my 'klunk').

    Jon /forums/images/graemlins/burb.gif
     
  5. Highlander

    Highlander 1/2 ton status

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    Re: \"klunking sound\"

    Hvae you looked at your tranny/ transfercase mount yet? or a motor mount.
    I would think if it was the drum you would hear a metal sound. You could get a buddy to ride next to you in a car a see if they can hear it and if so maybe they can tell where it's coming from.
    I once had a noise under my K5 and had the ol-lady drive real slow so I could walk next to it and see if I could find the noise.

    Eric
     
  6. rh88k5

    rh88k5 Registered Member

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    Re: \"klunking sound\"

    forgot to mention that the mounts are all good, I cant tell where it comes from, its not loud but I feel and hear it.
     
  7. imiceman44

    imiceman44 1 ton status

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    Re: \"klunking sound\"

    Well to give you some options.
    1-When you come to a complete stop, some trannies I had would after a few seconds kick in first gear and give this clunk, the fix is to adjust the idle speed.
    2-Another thing happened to me when the U bolts on the springs were loose the Blazer would slide on the springs until the pin hits the edge of the hole, tighten the springs.
    3-the drum brakes could do that if there is any fluid leak inside, check them.
    4-If the back lash is too much in your diffs or if the chain is loose in your Tcase it would clunk like that.
    If I think of something else I will let you know.
     
  8. dammit32

    dammit32 1/2 ton status

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    Re: \"klunking sound\"

    It definately sounds like a driveline klunk to me. I second the motion for grease on the slip yoke:) Mine does the same thing
     
  9. will89

    will89 1/2 ton status

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    Re: \"klunking sound\"

    What is the right type of grease to use on the yolk? Molybendum?... My 89 Sub does the same thing....
     
  10. bluboti

    bluboti Registered Member

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    Re: \"klunking sound\"

    my 90 k5 did the same ,pulled rear driveshaft put some teflon grease on trns case output spines.it stopped.
     
  11. trailblazer87

    trailblazer87 1/2 ton status

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    Re: \"klunking sound\"

    mattyblazer, my '87 did the same thing. Check the bar on the passenger side of the t-case, it might be broken, your rubber mounts to the crossmember could be loose or broken. Mine seem to like loosening up periodically, yours could be too. Thast thumping is the t-case movingaround. Mine got so loose it bent the floor upwards and also hit my muffler heat shield /forums/images/graemlins/eek.gif
     
  12. SAVAGE1

    SAVAGE1 1/2 ton status

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    Re: \"klunking sound\"

    I had a clunk because my transfer case cross member was loose. I'd also check the bolts to the adapter between the t-case and tranny.

    I also get the series of "thumps" when accelerating hard. I'm thinking this is due to axle wrap causing the driveshaft to bind... anyone have this problem too?
     
  13. TONYP

    TONYP 1/2 ton status

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    Re: \"klunking sound\"

    Rich, I had the same thing.....if you have a posi rear end the gear oil might need to be replaced, My truck felt like it wanted to lock up and not move...changed the rear end oil and its like new....
     
  14. imiceman44

    imiceman44 1 ton status

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    Re: \"klunking sound\"

    I don't know if you have it figured out yet, but there is one more thing I remembered, sometimes the spring pad gets rounded and the axle rocks back and forth because of it.
    That one is easy to check, just look at the adges of it, there should be no gap between the pad and springs on either side.
    The only solution to this one is a new pad, and it's not a common thing to happen, but it has happened and a couple of years ago in fourwheelr they had an article on it.
    Just one more thing that could go wrong.
    /forums/images/graemlins/grin.gif
     

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