Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Vibration under acceleration?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigk, Oct 28, 2001.

  1. bigk

    bigk 1/2 ton status

    Joined:
    Jun 13, 2001
    Posts:
    358
    Likes Received:
    0
    Location:
    Mendon Illinois
    Just replaced the rear u joint today. It didn't look good, only two of the posts had been getting grease. Didn't help the problem, though. Could it maybe be a motor or trans mount? Maybe old motor has a vibration?

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  2. taterblazer

    taterblazer 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    277
    Likes Received:
    0
    Location:
    Boise, ID
    umm, and the upper u joint to?
     
  3. Espen88k5

    Espen88k5 1/2 ton status

    Joined:
    Feb 19, 2000
    Posts:
    981
    Likes Received:
    0
    Location:
    Norway
    I would replace the trannymount if I where you. It made my shudder at takeoff disapear like that!*snaps fingers*[​IMG]
    Also check the upper u-joint if you didn't while you did the rear. My top u-joint had a tiny woble in the slip-yoke's "ears" that I fixed using some sement to seal the caps.
    Changing the trannymount is a 10 minutt jobb to, could'nt be easier.


    <font color=red><a target="_blank" href=http://www.espen88k5.alloffroad.com>www.espen88k5.alloffroad.com</a></font color=red>
     
  4. CaptCrunch

    CaptCrunch 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    3,596
    Likes Received:
    1
    Location:
    Minnesota
    what kinda vibe and what speeds? I assume it comes through the seat. Is it kinda grindy felling? Any noise?

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

    BIGDEAL Registered Member

    Joined:
    Apr 16, 2001
    Posts:
    27
    Likes Received:
    0
    Location:
    Waycross GA
    My Suberban has the thing at a speed of about 55+ I also changed the rear u-joint and am about to change the front. I'll let you what happens.
     
  6. MITCH_89'

    MITCH_89' Registered Member

    Joined:
    Dec 7, 2000
    Posts:
    91
    Likes Received:
    0
    Location:
    GULF BREEZE, FL.
    How involved is it to change the Tranny mount? Mine shutters a little under takeoff, But no time else. i have New u-joints, its always done it.

    BLAZE IT UP!!
     
  7. Espen88k5

    Espen88k5 1/2 ton status

    Joined:
    Feb 19, 2000
    Posts:
    981
    Likes Received:
    0
    Location:
    Norway
    It's not hard at all, I used my floor-jack and a wooden log to gently press the t-case upp, removed the two nuts on the crossmember, then removed the two bolts to the t-case. Gently continued to press upp on the t-case untill I could slide old mount out and new one in. 10-15 minuts tops.
    My old mount looked allright, but on closer inspection I could twist it almost twize as much to one side(accelration) than to the other. It was cheap to.[​IMG]

    <font color=red><a target="_blank" href=http://www.espen88k5.alloffroad.com>www.espen88k5.alloffroad.com</a></font color=red>
     
  8. Pugsley

    Pugsley 1/2 ton status

    Joined:
    Jan 16, 2001
    Posts:
    3,556
    Likes Received:
    0
    Location:
    Tucson, Arizona
    You'll need a 15mm deepwell, a 15mm wrench, and like Espen said, a jack setup to lift the case. That's about it[​IMG]

    ......And knowing is half the battle
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  9. bigk

    bigk 1/2 ton status

    Joined:
    Jun 13, 2001
    Posts:
    358
    Likes Received:
    0
    Location:
    Mendon Illinois
    Thanks for all the replys. My vibration is really just on takeoff or when I slow down to town speeds, and am under acceleration. Highway speed is fine. Do auto parts stores carry the poly mounts? Also, there is some leaking out of the pinion on the rearend, but the fluid level seemed fine, although it really stunk when I stuck my finger in it. But the rear isn't lifted, just an add a leaf in the front. I could definitely start with the mounts, since she's got over 185K on her. How big a deal is the top ujoint, it's a cv, right? How much trouble and cost? Thanks again.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  10. bigk

    bigk 1/2 ton status

    Joined:
    Jun 13, 2001
    Posts:
    358
    Likes Received:
    0
    Location:
    Mendon Illinois
    Hey Mikey, I guess I should have directed my reply to you, so you'll know when I did it. Not real sharp sometimes.

    Karl
    Temporarily Unemployed Underwear Model
    87 3/4 ton
     
  11. Pugsley

    Pugsley 1/2 ton status

    Joined:
    Jan 16, 2001
    Posts:
    3,556
    Likes Received:
    0
    Location:
    Tucson, Arizona
    The poly mounts are impossible to find - Energy Suspension lists it, but nobody carries it. The OEM type rubber one will run you about $20 at any given parts store. As for the U-joint, it's cake to change - just a single straight joint, no CV.

    ......And knowing is half the battle
    <a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
     
  12. Twiz

    Twiz 1/2 ton status

    Joined:
    Mar 8, 2001
    Posts:
    3,729
    Likes Received:
    0
    Location:
    Clearfield Ut.
    Stick with the rubber mounts. Poly mounts can be trouble! (vibrations, cracked transmission case etc.)

    Gear lube smelled bad.... burnt?
    Not a good thing, change it! Check the gears for pitts and wear, metal in the lube, etc.
    Bad gears will usual cause a noise, not a vibration (usualy). Genneraly releated to excell or decelleration. More pronounced at freeway speeds. Also, very speed related.
    *see "Randy's Ring and Pionion" site for a excelent description*

    Drive line (train) vibrations are more of a "boom" kinda thang.
    Also, speed related, sometimes excell/decell. Best bets to pull the drive-line out and check the joints by hand. "detents" in the joint travel is a sure sign it's bad. It should travel evenly and smoothly, with very little resistance.
    You put in a new joint in the back, is it "preloaded"? Shouldn't be. (work it by hand, low resistance, no detents). If it is too tight, the caps are on too tight. lay it on the free cross shaft and useing a scocket over the yoke, a light smack with a hammer should seat the C-clips.

    On the T-case side.
    Before removal, check the yoke to t-case out-put play. Grab the yoke and push up and down, if there is a defent "clunk clunk", than the yoke and/or bearing -maybe- bad.
    Than remove the driveline and check the joint.

    Other common causes to a vibration on excell;
    - bad moter or trans mounts, allowing the engine to "ground-out" under force.
    - poor u-joint angles under excell, basicly, the rear u-joint angle changes only under excel due to lift/soft springs/soft shock/etc. Not likely in a mostly stock ride.
    - exhaust grounding out on a cross member etc.. under load the engine tweeks over, taking the exhaust with it.

    Hope this helps some.

    <font color=blue>Twiztid</font color=blue><P ID="edit"><FONT class="small">Edited by Twiztid on 10/29/01 09:15 PM.</FONT></P>
     
  13. mudmover

    mudmover Registered Member

    Joined:
    May 13, 2001
    Posts:
    20
    Likes Received:
    0
    Location:
    Southern California
    I chased a vibration like that on my blazer...argh it was annoying. only on takeoff i would feel this wobble wobble...I replaced both engine mounts, trans mount. still there. checked u joints, etc. all good. I (currently) have the 208 trans case with the slip yoke driveshaft, found the problem to be the output bushing. the yoke on my drive shaft was scored pretty bad, but cleaned up with emery cloth. Motor mounts would probably clunk on accel. easy way to check is to powerbrake it (on and off, on and off) while a buddy watches the engine's movement. if it lifts real bad, replace those mounts. if not, i would be looking somewhere else than mounts.

    What do you mean you cant run <font color=red>35's</font color=red> and an <font color=red>easy locker</font color=red> and <font color=red>3:08's</font color=red> in a <font color=red>10 bolt</font color=red>?[​IMG]
     

Share This Page