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Driveline woes...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by scott87, Nov 29, 2001.

  1. scott87

    scott87 Registered Member

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    I think I know the answer to this, but just wanted to get some more input. On my 87K5 I put in a 4" shackle flip and a 1" ORD block. Vibrations were horrible. I measured for a CV Shaft. Installed that today. Better, but vibrations still there. I checked the slope of the driveshaft and compared it to the slope of the end yoke at the diff. There is a difference of about 4-5 degrees. Didn't check that before i got the CV shaft. Anyhow, is this angle difference the main source of the vibration? I feel silly for asking about this, but just want to cover some bases before getting too frustrated.... Any opinioins?

    scott
     
  2. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    So you have the CV joint dl AND vibration? I think I do also.

    I thought with the CV you were guarrenteed no vibes.....?

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  3. BorregoK5

    BorregoK5 1/2 ton status

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    You did point the pinion on the axle at the tcase right? It should only be a couple of degrees down but relatively straight at the pinion.

    I started with nothing and I still have most of that left! - <a target="_blank" href=http://www.echobit.com:81/k5/> Pictures</a>
     
  4. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Borrego is right. The pinion must be almost directly in line with the drive shaft or a CV shaft will not work right. A few (1 or 2) degrees down on the pinion is preferred because axle wrap when accelerating will tilt it up by that much.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  5. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    I'll ask the dumb question since it is only my 504,639,756th.... How do you adjust for this correct angle?

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  6. kpanza

    kpanza 1/2 ton status

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    You have to point the pinion right at the t-case output! It should actually be DOWN by one degree for the optimum situation (torque pulls it up one degree, so you compensate by going down one degree!)

    If you didn't do this, that is probably the source of the vibes...and if you have a slip yoke t-case some people think it will give vibes worse than the fixed yoke. I have the 4" shackle flip also and have shimmed the rear end to be almost equal to the case (no cv shaft for me) angle, and I still have vibes at higher speeds...
     
  7. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    To go from a standard shaft to a CV you generally must cut off and realign the spring mounts.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  8. scott87

    scott87 Registered Member

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    how is this done, i.e., pointing the pinion at the t-case? do you mean shimming the pinion? the driveshaft sits at about 20 degrees slope. The pinion is about 16 degrees. So, shim it up to 20 degrees?
     
  9. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Thanks BadDog. That might mean relocating my shock mounts also if the rotation needed is grat enough.

    I'll go take a pic and see what y'all think.

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  10. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Not good pics but it loks like I am in that 2 degree range. But I dont have radian eyeballs..... I will be lifting to level this weekend so I will check it out.

    http://coloradok5.com/gallery/album35/aal

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  11. Hossbaby50

    Hossbaby50 3/4 ton status

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    Sorry to get off subject, but nice sliders. Did you make them? If not where did you get them? Just wonderin. Thanks

    My Chevy isn't broken, its just out of gas.
     
  12. 2Dogs

    2Dogs 1/2 ton status Premium Member

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    Thanks.
    Bent and Twisted in Chico Ca
    (530)342-3003
    Mike Ladd

    Mike builds AWESOME roll cages and accesories.

    Dave

    Horn Broken... Watch For Finger.
    <a target="_blank" href=http://coloradok5.com/gallery/Daves-Pics>http://coloradok5.com/gallery/Daves-Pics</a>
     
  13. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Hard to tell at that angle but it does look like the pinion needs to be raised. You need to use one of those angle finders to see exactly what needs to be done.

    Russ

    85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked
    Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.
     
  14. JIM88K5

    JIM88K5 1/2 ton status

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    Wow Scott,
    I have the same set up and I just got my CV shaft and installed
    it today but with better results. My pinion angle is a little low
    but I think it's acceptable. It does not vibrate at all. YAHOOO....
    It was not an out of control vibe before but it was not right.
    My transfer case has the lowering spacers but I want to take those out. Then I will have to shim the pinion up a few degrees. Boy am I stoked about that drive-shaft !!!

    88 5.7 5in lift 35"procomp at's
    700-208-456-3in exh w/flowlowder 10 bolts & some ORD stuff
     

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