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Drivelive Vibration, On Hwy Only, Trans Or T Case?

Discussion in 'Early CJ5 and CJ6 Tech' started by 70cj5134f, Aug 26, 2018.

  1. Sep 9, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Better, I can't feel in wheel or pedals, but metal junk in tub still vibrates some.
    All joints tight, sliders tight. Rear angle is 17deg on axle end and 22deg on t case end?
    Next I'll remove rear shaft and be sure it goes away?
    Vibration seems worse when gently accelerating, when u pedal to floor, no vibes?
    Chasing dragons?
     
  2. Sep 9, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Or should i remove the poinion shims to get joints parallel?
    Or shim the t case cross member down a bit?
    Thanks.
     
  3. Sep 13, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    With rear shaft out, no vibes?
    I'm thinking it's my pinion shims possibly?
    U joints, not parallel.
    I'm going to remove pinion shims and try.
    This gets them close to parallel.
     
  4. Sep 13, 2018
    TIm E

    TIm E Aggressively average

    NW Arkansas
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    Unless we are talking about different terminology, the pinion shims only set the preload on the pinion bearings. The set-up for those is no end-play, in fact, you want it to have 16-18 in/lbs of rotational torque if I remember correctly. If you yank on the pinion yoke and there is slop, maybe. I suspect you are talking about the pinion angle shims between spring and axle perch, if so, that is definitely worth a try.
     
  5. Sep 13, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    I'm talking bout shims( wedges) that set the pinion angle, spring pad to spring,
    Not preload shims, my bad? Pinion pointing up toward t case.
    If I remove the axle shims (wedge), it will be close to parallel to t case.

    I set it up on Jack stands today, started up, 3rd gear just idling.
    Rear end was bouncing up and down , at the stump.not constant but some.
    Everything is tight, no play in pinion, u-joints tight, drive shaft and axle spin free
    By hand, no drag or rough spots.no excessive play in ring and pinion.

    I'll remove wedges tomorrow and try it?
    Any other ideas?
    Thanks
     
  6. Sep 13, 2018
    baldjosh

    baldjosh Member

    pacific north west
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    no load...gotta have a load or drag on it
     
  7. Sep 13, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    6,656
    Under the frame or under the axle?

    If under the frame, I'd expect that if the joints are being allowed to exceed their limits, or if they are of unequal angles. Drooping the suspension will accentuate the issues.

    If under the axle, you're more accurately mimicking ride height. If you have axle movement then, something is definitely out of phase, or the angles are way off.
     
  8. Sep 14, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    I actually had 2 jacks, 1 under each spring pad, shock mount.
    Load on suspension.
    Driving on road, it vibes on acceleration, and under deceleration, but if u just
    lightly touch the gas, no vibes?
    I googled shaft phasing couple nights ago, and this is the only thing
    that I can see that's incorrect?
    All ideas welcome, hope to have a report tomorrow.
    Thanks.
     
  9. Sep 14, 2018
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Worn u-joints. Or worn ring/pinion in the differential?
     
  10. Sep 14, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    This is unclear. It is incorrect?

    Take your shaft out and set it on a flat surface. The flat sections of the yokes (where the u-joint caps are) should rest perfectly even on the table. If they don't, your shaft is out of phase.

    While the shaft is out, and with the jeep level, place a magnetic angle finder on the face of the yoke on the axle, then on the face of the output flange at the parking brake. These angles should be the same.

    Either of these conditions (if wrong) will cause vibration as you'll feel the shaft speeding up/slowing down on every rotation.

    And as Pete suggested, check the condition of the u-joints, and the in/out and rotational play in the pinion while you have the shaft out.
     
    Hellion likes this.
  11. Sep 14, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    1 shaft is clocked correct.
    2 Rear angle is 17deg on axle end and 22deg on t case end?
    This is what I hope is the problem.
    By removing the wedges (i installed these under advise from a jeep shop ,lol)
    The angles will be close to parallel.
    To my understanding , the shaft should be clocked, and parallel.

    Ps is 20-22 deg too much? I've seen jeeps with way more lift than mine with stock shafts?
     
  12. Sep 14, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    It depends on the elevation difference and distance between point A and point B. 20-22° Sounds like a lot, but if your shaft sits at 19° when installed, thats only 1-3° of misalignment.

    I'd start with trying to match the input/output angles and see if it helps.
     
  13. Sep 14, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    22° does sound like a lot though. Your engine must have quite a tilt to it?
     
  14. Sep 14, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Engine and trans, in stock location.
    Rear end is what has been changed.
    With the YJ spring conversion,I got wheelbase within 1 in of stock.
    2in lift from springs, 1in from shackles,and bout half inch from oak body mounts.
    The t case points straight back like stock, but the pinion points kinda up toward tcase.
     
  15. Sep 14, 2018
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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  16. Sep 14, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Well it worked, no vibes, But (theirs always a but), now with the suspension hanging, with no load on it
    the u joint bumps itself when rotating by hand. No problem on road, or crawling in my own rock, rutted,flexing trail, but is this safe?
    Does someone make a cardian (think i spelled it wrong)joint conversion, or is their another fix, or leave it alone?
    Thanks
     
  17. Sep 14, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    You can either run a limiting strap of some sort to limit the travel, or take your chances - in theory, the only time the axle will droop that far is when you're airborne. Of course there are exceptions...

    With a double cardan shaft, you'd have the double joint up at the t-case, and you'd have to cut and turn the spring pads to rotate your axle so the bottom joint has zero angle (pinion should be directly in line with the driveshaft).

    Personally, I'd run it as-is until you have a problem, then upgrade to a new double cardan shaft if you feel that's an option.
     
    47v6 likes this.
  18. Sep 14, 2018
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Tom Woods, as referenced already.
     
  19. Sep 15, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Thanks for link.
    So for 299$ plus 60$ yoke, I could go built proof?
    Or, that old saying, if it ant broke don't fix it?
    Or, they mention yoke grinding for clearence? (This is a mabe),it just barley binds.
    Or a limit strap? this also a mabe?

    Need ideas on building a limit strap,
    What material, and where to attach?
    I think for now the ant broke don't fix it will do!
     
  20. Sep 15, 2018
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    I have a limit strap on my 3b. It is attached to the front of the casting at the pinion. It allows the suspension to flex at full capacity, while keeping the u-joints in check while airborne.

    I took the locking mechanism out of an old seat belt, shortened the webbing and used it as the limit strap. It keeps tension on the strap so it doesn't get caught up in the driveshaft. I'll get a pic of it when I get home tonight if I remember.
     
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