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vibration

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Dunc03, Feb 22, 2002.

  1. Dunc03

    Dunc03 1/2 ton status

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    I have alot of vibration with increased RPM and MPH. Its really bad when i let off going about 65-70. I've replaced both the ujoints onthe rear drive shaft, and the front one dosen't look like it needs it. I checked the motor mounts and didn't see any cracks. Could it bethe harmonic balancer. Got any idea?
     
  2. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    did you over tighten the u bolts on your U-joint? that can lead to eating up u joints. also is your Drive shaft balanced? and check your yolk on the diff end. it might be eaten up from a previous bad joint.
    that is just a few places to start. aldo to see if if is you drive line put it in first and hold the rpm you get the vibe in, then do it in second. then third and if you have 4th.
    if it is just in the certian RPM it can be engine.
    Grant

    take me drunk, i am home
    www.geocities.com/seventy4blazer/parts4sale.html
     
  3. CaptCrunch

    CaptCrunch 1/2 ton status

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    where do you feel the vibration? feet, seat of the pants? Have you lifted or changed anything lately? If so check you driveline angles... have you hit anything or wheeled it and may of kit a weight off the drive shaft or dented it? If the answer is no to all of these and seems to be from the rear then I would be guessing one of the bearings in the diff is going bad, most likely a pinion bearing, buty kinda hard to say w/out more info

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  4. Dunc03

    Dunc03 1/2 ton status

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    the vibration seems to be coming from where the tranny is, like the troque converter bolts are lose, but they are not. I haven't hit anything solid with the drive shaft, i might dragit through some sand from time to time. No lift or anything, and the only thing I've done to it is change the ujoints. I changed the one that can be unbolted, and my mechanic changed the one on the yoke. Both ujoints went out about a month apart, so maybe there is a problem with the drive line, or it could just be the fact that my trans has massive amounts of slack, which jerks the hell out of the thing when it shifts from 1st to 2nd. I guess i should be thanksfull that i am still on the stock motor and trans, which have 188k miles on them, with no magor work except for a valve job. thanks for all the help man
     
  5. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    classic slip yoke drive shaft vibe...

    get a fixed one and decent cv shafts and you'll be SET.

    J


    See the on-going build up of my '85 Jimmy! <a target="_blank" href=http://community.webshots.com/user/jekbrown>http://community.webshots.com/user/jekbrown</a>
     
  6. shawnboy

    shawnboy 1/2 ton status

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    Check the bearing in the output shaft housing. Went through hades till I figured that one out.
    Shawnboy.

    <font color=red>If you are having too much fun it's probably illegal.</font color=red>
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

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    I would probably drain the tcase and check the output bearing while you have it drained. Inside the drain whole of the tcase is a magnet... check it for large amounts of sludge or metal. If all of that is a no, then I would pull the cover off the rear diff and look for metal and what not. Depending how ambishis (sp?) you are you could pull out the axle shafts and see how the wheel bearings are and could even pull out the carrier and spin the pinion to check those bearings.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  8. 1BAD88

    1BAD88 Registered Member

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    I also had that problem around 60-70 it turned out to be that my tranny-t-case seal was leaking onto the t-case mount and made it weak .So I replaced it with a poly mount and it cured the problem.hope this helps good luck

    1988 k-5 blazer 5.7
     
  9. or2play

    or2play 1/2 ton status

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    Check your axle bearings. I have almost the same problem, about 50 and up the whole truck vibrates. I can feel it in my foot. I found out my driver side axle in the 12 bolt rear end is gone. The axle is most definatly toast. Easy way to to check is to jack up the rear end so the tires are of the ground. Put the truck in drive and watch the tires spin. If they woble at all, thats the problem. Also make sure your tires are balanced.


    Brian
    74 Suburban 350/TH350/NP203... Soon to be 205 w/ORD Doubler
    http://doors.cybertrails.com/~or2play
     

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