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Vibration Update, ???

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by txguy, Oct 18, 2001.

  1. txguy

    txguy 1/2 ton status

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    Since posting this last night, I have changed out the U-Joints on the rear. Last nights posting, "I think this may have started a day or two ago, and now its very noticable. Overall vibration throughout the cab. Doesn't seem to be coming from a particular place. Steering wheel is receiving some of it, but seems to be less than the cab, or at least the noise being created in the cab. It most harsh between 25ish to 40ish MPH. Lower than that, don't notice anything. Higher than that it is still there, but the amplitude lessens as speed increases. I have ran the auto tranny through the gears manually to give varying RPMs. Does not seem to change behavior. The vibration frequency increases as the speed does. The kicker is, when I let off the gas, it stops completely, and when I get back on it, it starts again. HELP!!! If I floor it from say 30, and it loads things up, it doesn't make it worse... Anyone??? And, there does not seem to be any difference if I am going up a hill, down, or on level ground. If there is, it is not much. This is in 2hi. I have tried it in 4 hi, hubs free, no difference. Have not had a chance to engage the hubs, or try it in low." Now that I have changed the U-Joints, still have the same vibration. Anyone have any other suggestions on what might be causing this? Anyone?
     
  2. txguy

    txguy 1/2 ton status

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    Anyone?? Is it possible the rear end could cause this?
     
  3. backlash

    backlash 1/2 ton status

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    Torque Converter? Is the tranny a fresh rebuid? What else was done to it recently? The u-joints made no difference? ... at all?
     
  4. Stoopalini

    Stoopalini 1/2 ton status

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    Maybe the rear end having problems? Do you have any fluid leaking out of the rear? Specifically out of the pinion? If so, that may be your problem.

    Have you opened up the rear diff yet? If not, open it up and inspect everything in there. If nothing else, it will give you an excuse to change out the diff fluid.

    Thomas.

    -- '84 1-Ton Blazer --
    When the goin' gets tough,
    the tough go 1-Ton [​IMG]
     
  5. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    I just got rid of a similar problem and this may be the case for lots of these mysterious shakes and rattles before and after u-joint changes

    The straps that hold the rear u-joint to the rear axle on mine are worn pretty bad...looks like they have seen their days of abuse somehow by the previous owner or something...anyway I had to get underneath and take off both straps and twist and flip them until similar abuse markings lined up...like scratches with scratches and extra bubbly metal with extra bubbly metal on the strap when turned the right way like up and down but not side to side and then rotate teh rear driveshaft and I'd side to side but not up and down....get the idea?

    Believe it or not this really made a difference....Then again my symptoms were that no matter how tight the bolts on the straps the rear drive shaft had movement in only one direction...also as I'd slow to a traffic light i'd hear a soft clunk clunk clunk as speed would decrease....a strong vibration when i'd nail the gas or run at certain speeds and RPM's violently vibrated the cab just from a 1/4-1/2inch of play back there....i really thought my truck was about to come apart on me at high speeds to the point i was scared to travel and did not travel on some days because of this....what a relief that it was only this...hope yours is the same....check it out

    What? You think the hole is too deep? Lemme see...
    1985 GMC C-10 Shortbed
    1984 Chevy K-5 Blazer
     
  6. CaptCrunch

    CaptCrunch 1/2 ton status

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    What's the stats on the truck? Is it lifted and if so how much?

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  7. ftn96

    ftn96 1/2 ton status

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    Sounds like driveshaft vibration from angles or the shaft is out of balance.

    Surgeon General's Warning:
    Viagra and steroids may be harmful to your spouse![​IMG]
    <a target="_blank" href=http://www.nashvillek5.freeservers.com>www.nashvillek5.freeservers.com</a>
     

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