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drivetrain vibration

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by gbfan, Oct 6, 2004.

  1. gbfan

    gbfan Registered Member

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    tried posting in the garage but got nothing so I will try here. I have a 72 blazer 8" suspension lift 38" PJ's at about 40 mph a pulsating vibration starts and gets worse as i go faster. rides great up to 40 and it starts. high angle drive shaft pinion angle set one degree low to allow for torque. Tire balance is good. I am at a lose from what i have read if i drive it long enough like this I could throw the drive shaft. Help!!!!
     
  2. BobK

    BobK 1/2 ton status

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    If you have acces to another set of tires and rims throw them on and see if the vib. is still there.
    That way you can at least rule out the rotateing mass of the tires.

    You mentioned the new driveline so it's prob. not it but just to check,take out the rear shaft and throw it in 4wd.You can rule out the rear drive line if only the front is moving.

    Maybe check the flex plate bolts?Slightly loose bolts may cause the vib. as well.

    Just a couple suggestions anyway.
    Goodluck!
     
  3. gbfan

    gbfan Registered Member

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    well I changed the harmonic balancer, checked flex plate bolts, driveshaft angle, rear ring and pinion. shot some grease into all the u-joints still no dice. pulled the driveshaft off and checked out the output yoke. I have a little in and out movement. maybe time for a transfer case rebuild. could a sloppy output yoke cause this vibration? i am also going to have the driveshaft checked for balance just in case thanks for the suggestions anything welcome
     
  4. gbfan

    gbfan Registered Member

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    may have figured it out... something to check for with drive train vibration. u-joint caps on the cv-joint and at the differental need to be straight in line. if you lay it on the floor use an angle finder lay it on one side u-joint cap and then the other they should be the same. when i had the drive shaft made the guy welded the tube in with the u-joints 8 degrees off causing to fight each other.fingers crossed it fixes it...
     
  5. spearchucker

    spearchucker 1/2 ton status

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    I'd place money on that being the problem. /forums/images/graemlins/thumb.gif
     
  6. backcountry

    backcountry 1/2 ton status

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    [ QUOTE ]
    well I changed the harmonic balancer, checked flex plate bolts, driveshaft angle, rear ring and pinion. shot some grease into all the u-joints still no dice. pulled the driveshaft off and checked out the output yoke. I have a little in and out movement. maybe time for a transfer case rebuild. could a sloppy output yoke cause this vibration? i am also going to have the driveshaft checked for balance just in case thanks for the suggestions anything welcome

    [/ QUOTE ]

    You stated that you replaced your harmonic balancer. Did you have it balanced as per your old one? /forums/images/graemlins/dunno.gif
     

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