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Vibration ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by wayne, Oct 27, 2001.

  1. wayne

    wayne 3/4 ton status

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    I have a vibration at about 60 and it goes away when I put it in nutral or just get off the gas. I figure it is not tire balance so should I try to shim the rear axle a little more or drop the t case more. I have almost 5" of lift and 35's.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  2. taterblazer

    taterblazer 1/2 ton status

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    I would start with replacing both rear u joints and the straps.
     
  3. wayne

    wayne 3/4 ton status

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    All of that is only 5 days old.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  4. ftn96

    ftn96 1/2 ton status

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    How much shim and t-case lowering have you done?
    And is the driveshaft balanced good?

    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>
     
  5. wayne

    wayne 3/4 ton status

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    T case is dropped just over an inch. The rear angle is about 3 degrees I think. I am going to drop the case a little more when I make my new spacers. The driveshaft balance I am not sure about but it saw 90+mph with no lift and 31's with no vibes. The vibration is not that bad but it is noticeable. I don't want to put any more money in the shaft because I am going to a 400/205 soon and will have different shafts then.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  6. CaptCrunch

    CaptCrunch 1/2 ton status

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    Yeah what kinda stuff you have out back? Did you get the driveshaft lengthen with the lift? Still have a slip yoke? Stock style shaft or CV? Pinion angle? Tcase drop? Shackle flip out back?

    Alot of different things here... propably one of the most common is if you went w/ a shackle flip. I know some guys are running it ok, but seems like a fair share also have vibes even w/ the correct angles after a lift. Another item I can think of is did you make sure to refill the tcase, would of had significant drainage which would be enogh to cause a vib at freeway speeds.

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

    wayne 3/4 ton status

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    Stock rear shaft, slip yoke, no flip yet, using blocks [sigh] that have angle in them plus I dialed in just a bit more angle when I relocated the purchs for the ORD 1" zero rates and the 14ff gives a little lift compared to a 10 bolt.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  8. yunit

    yunit 1/2 ton status

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    I actually angled my axle down about 2 degrees and my universal angles are just about perfect, but I have not driven the truck yet. It also looks like I will drop the tcase about an inch too.

    1987 Jimmy Sierra Classic, Palisades Park, NJ 07650
     
  9. CaptCrunch

    CaptCrunch 1/2 ton status

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    I would say check those angles. Maybe go pic up an angle guage so you can be positive.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
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  10. ftn96

    ftn96 1/2 ton status

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    Ok, now you said you have almost 5" lift. Did you get BDS or did you get a 4" thats running a little high?
    If you have 5" lift and a 3 degree shim, that is most likely where your problem is. You dont want to lower the T-case any more than you have to. It will put more strain on the motor mounts plus it makes you fan get closed to the fan shroud.
    If Im not mistaken, the general rule of thumb is 1 deg for every inch. I have a 4" lift and I have a 4deg shim. So if your shim is anly 3 deg adn you have the 5" lift your working angle at the pinion is way more than it is at the T-case. However, the slip yoke could be a small part of the equation. It seems to me that the driveshaft was a tab bit shorter after swapping my 10 bolt to the 14 bolt. Seems like it would be opposite, but hell I could be drunk too. [​IMG]
    Any how if the slip yoke is not far enough in at the t-case, this can cause some vibration too.

    My advise, good or bad as it may be....Install a 5deg shim in the rear, leave the T-case the way it is and go from there. Might want to get an angle finder from Harbor freight and be done with the guess work. They are real cheap.
    Hope I was of some help.!
    Welcome to the "TON" group. LMAO!!!!!!

    Surgeon General's Warning:
    Viagra and steroids may be harmful to your spouse![​IMG]
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