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why then and not now?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Kelboski, Aug 3, 2000.

  1. Kelboski

    Kelboski 1/2 ton status

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    my 84K5 vibrates when it shifts into 2nd gear while in "D" only. if i give it enough gas, it won't vibrate, when i give give it little nough gas, it won't vibrate, but just in between a little and alot, it shakes when going into 2nd. it NEVER does it in overdrive though. just in drive...it's a 700r4...:(, i've had my K5 for 3 months now, and its done it since i first had it...its no worse than its ever been, but its very strange, and is starting to irritate me.
    Kelboski
     
  2. Kelboski

    Kelboski 1/2 ton status

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    has anyone ever had this happen?
     
  3. ggallin13

    ggallin13 1/2 ton status

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    It's probably your driveline. Drivelines are actually precision items, and if they are out of "true" even a little they can shake like hell.

    Either your driveline is out of "true" or you need to get them adjusted for length. From the sound of it it only needs to be balanced. Very cheap if you go directly to the driveline guy. Find the guy in your area and have him check it out. All the ones around here check drivelines for free, they should wherever you are, too.

    Stay away from the tranny shops if at all possible. Hope this helps, and keep me posted on what you find out!
     
  4. Kelboski

    Kelboski 1/2 ton status

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    ggallion, thanks for the info, can you tell me something about the vibe in drive, but not overdrive?
     
  5. Kelboski

    Kelboski 1/2 ton status

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    sorry...ggallin13..mispell
     
  6. Ressurection

    Ressurection 1/2 ton status

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    I agree, one other "driveline" thing to check, is- are the bolts holding tranny bellhousing to the block tight? My dad's 73 shook like hell, we checked them and were able to tighten some of them several turns, the heads of the others were actually (from vibration) embedded into the bellhousing case.

    You can't beat going Topless!
     
  7. Kelboski

    Kelboski 1/2 ton status

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    i REALLY appreciate the info fellows, but what would cause the shake in drive....but NEVER in overdrive?
     
  8. Kelboski

    Kelboski 1/2 ton status

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    and also...maybe a dumb question...but, what exactly does the "driveline" consist of?....is it the motor..tranny..trannycase...driveshafts..ect?
     
  9. Kelboski

    Kelboski 1/2 ton status

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    can anyone tell me why the vibe in d, but not overdrive?
     
  10. Kelboski

    Kelboski 1/2 ton status

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    guess i'll wait until tommorow for an answer...good night
     
  11. delta9blazer

    delta9blazer 1/2 ton status

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    i'd guess that the engine and tire rpm cause the vibration in drive. vibes are a tricky thing. very small input variances can exagerate or diminish the effects.

    my truck makes a little jangly noise on occasion (i think it's the cat going bad), and if i let off the throttle a little, or step on it a bit more, the noise goes away. same deal.

    the driveline is the long metal stick that connects your rear axle to the transmission.
    the drivetrain consist of the rear axle, driveline, transmission and engine.



    <font color=purple>delta9blazer</font color=purple>
     
  12. 6.2Blazer

    6.2Blazer 1/2 ton status

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    I really don't know any reason why having the shifter in either D or OD would make a difference since the vibration is occurring when shifting into 2nd. The transmission should behave the exact same in either D or OD when shifting into 2nd, the only difference is the trans is locked out of shifting into OD when the shifter is in D.
     
  13. ggallin13

    ggallin13 1/2 ton status

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    The internals of the tranny are different when in drive vs. overdrive. That's why it won't go into overdrive when in "D". All it takes is a subtle difference and you can really feel it.

    The driveline is the metal tube that goes from the transfer case to the rear end. That includes the u-joints as well. In your situation, you could have a bad u-joint, a dent in the driveline, or any other thing that will throw things out of balance.
     
  14. Kelboski

    Kelboski 1/2 ton status

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    so the driveline is actually the driveshaft....thanks for the info fellows...alot....keep um coming...i'll check it out and update you...thanks
    Kelboski
     
  15. jarheadk5

    jarheadk5 1/2 ton status

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    Vibrations are funny. All of the above reasons are possible causes. There are others, too.
    1. Different metals resonate at different frequencies. It is actually possible for a perfectly-balanced driveshaft to come apart explosively when spun at the right (wrong) speed.
    2. If you have a vibration in one gear but not others, it could be an internal tranny or engine problem.
    3. If the vibe comes at the same vehicle speed regardless of engine RPM or gear selection, it could be driveshaft, axle, wheel, tire, or suspension.
    Obviously, hunting vibrations down is tough. On my helicopter, we have a computer with tachometers and accelerometers to analyze frequencies and intensities in about 30 locations, and it can STILL take days of ground runs and flights to isolate and fix problems.

    Too bad I can't run it on my Blazer...

    [​IMG] Semper Maintenance!
     
  16. Blazerbob

    Blazerbob 1/2 ton status

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    My blazer did this also and it turned out the rear u-joint was bad and at a bad angle. Someone had put add-a-leafs on and it caused the driveshaft to be short also. After getting longer shaft and T-case dropped it is all better. Are there add-a-leafs on yours? Just a suggestion.

    <font color=blue>Blazerbob</font color=blue>[​IMG]
     
  17. Kelboski

    Kelboski 1/2 ton status

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    i don't have any add-leafs, but i do have a 4" susp lift,w/blocks in the rear. it made the vibration before i put the lift on though..still does it, but only when the tranny(700r4) is in "d"...it never happens in "od"....i can be accelarating in drive, hit 2nd, and the vibration comes, if i put it in overdrive at the moment the vibe comes, the vibration goes away, it will also go away if i give the throttle more gas.... but the vibe NEVER occurs in overdrive.......was your's like this?
     
  18. 6.2 man

    6.2 man 1/2 ton status Premium Member

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    I'm thinking the lock up converter maybe acting up .
     
  19. Kelboski

    Kelboski 1/2 ton status

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    could you tell me the symptoms of a convertor going bad?...i kinda know ehere it is, how expensive is one, and what does it take to install a new one?,,,tranny removal?
    Kelboski
     
  20. 6.2 man

    6.2 man 1/2 ton status Premium Member

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    The one that went bad felt like I was driving over railroad tracks at around 15 to 25 mph. Yes , the transmission has to come out . It's between the engine and transmission . Make sure that is it before going through that much trouble . I paid about $ 170.00 for the converter a lone .
     

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