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Vibration!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 4x4blazer, Aug 11, 2001.

  1. 4x4blazer

    4x4blazer 1/2 ton status

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    I have a bad vibration once I hit about 30mph. It seams like it is only when I try to accelerate. I havent gone over 30mph since I noticed it cause I am afraid I might hurt somethin.
    Any ideas what could be causin this?
     
  2. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Could be a bunch of things- loose exhaust, bad u-joints, cracked flywheel.........Get under the truck and take a close look.

    Can you better describe how it feels?



    <font color=red>PHOTO ALBUM-</font color=red> <a target="_blank" href=http://albums.photopoint.com/j/AlbumList?u=1289798>http://albums.photopoint.com/j/AlbumList?u=1289798</a>.......<font color=blue>TRUCK & HIKING PICS</font color=blue>
     
  3. 4x4blazer

    4x4blazer 1/2 ton status

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    New 350 motor has only about 75 miles on it, new th400 has only about 100 miles on it, new rear end from hub to hub has only 30 or so miles on it, just replaced u-joints (back drive shaft).
    The vibration is violent. Makes the whole dash shake real bad.
    When I am going about 25-30mph and give it gas to accelerate, this happens. But if I let off the gas and coast, it stops.
    (It shakes so bad my glove box opens and everything flys out, CB falls off dash, etc...)
     
  4. bigblue

    bigblue 1/2 ton status

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    wow, i was thinking driveshaft. Mine was vibrating in the 25-30 MPH range like yours. But not as violent. Did you just get a lift put on?
     
  5. ftn96

    ftn96 1/2 ton status

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    Mine did this only after a 4" lift and not lowering the T-case.
    Nothing else that I can think of would cause that strong a vibration other than some REAL bad Ball-joints or something got JACKED when you swaped those rear U-joints.

    Tip here. U-joints that are brand new are tight but when htey get worn they tend to get real nice and smooth and then WHAM they break. I've noticed that, since I installed new joints the truck rode like A, but then as the joints started to break in and ware they got smoother. Then at my last serviceing with the grease gun, WHAM the truck was vibrating again. Now after 500 miles or so it is starting to smooth out again.
    Im thinking they were worn when you got it because adn under lying vibration has taken its toll. Now you got new joints in there and they are tight, now you are feeling the full effect of the vibration that was previously underlying.
    Again this is just my theory. Take it at that and nothing more![​IMG]

    Does anyone have a grinding disk I can borrow?[​IMG]3/4 in progress[​IMG]
    <a target="_blank" href=http://www.nashvillek5.freeservers.com>www.nashvillek5.freeservers.com</a>
     
  6. 4x4blazer

    4x4blazer 1/2 ton status

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    No new lift. Maybe I did jack somethin when I put the new u-joints in. I will drop the shaft and check everything out.
    Thanks for the input.
     
  7. Panther

    Panther 1/2 ton status

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    Try to look at the shaft itself. Look for discolored spots. Maybe you knocked off a weight from the shaft.

    No offense at all, but have you grease-gunned the joints? I had a dealer replace mine one time and they didn't bother to grease them. Luckily I checked them a few days later.

    <font color=blue>Brilliance is like 4wd, it allows you to get stuck in a more remote location [​IMG]</font color=blue>
     
  8. TwoCrowsDesign

    TwoCrowsDesign 1/2 ton status

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    Sounds like what was happening to me a while back. Went through the whole drivetrain thing, but it turned out to be ignition failure. You'd be amazed how much a 350 can wobble when its only running on 5 cylinders.

    John

    John
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Make sure the reaining clips (if it uses the C-clips) are not clamped under the straps. Sure sounds too violent to be a bad u-joint though, I was hitting 45 easily with very little vibration yet the u-joint was toast, and so was the yoke. You will probably do well to check the pinion yoke nut for tightness also, they tend to loosen up.



    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</a>
    No anti-theft measures on your truck? No pity when its stolen
     
  10. 4x4blazer

    4x4blazer 1/2 ton status

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    Thanks for all the input guys.
    Right rear u-bolt was loose, a little lock-tight and snuggin' and runs great now.
    So you can all call me "dumb" names now, lol.
     
  11. RESTORE89

    RESTORE89 1/2 ton status

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    we aint smart nuff ore selve to calls you no names

    It needs a bigger motor.
    what's in it now?
    doen't matter it NEEDS A BIGGER MOTOR
    89 350tbi/700r4h/np208/4.11's
     
  12. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    That's what great about this site. We get to learn from other peoples mistakes. So hopefully we won't do the same thing.......Dan

    If it ain't broke.......Don't fix it....
     

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