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.

help with vibration

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Gary 86 K5, Nov 16, 2002.

  1. Gary 86 K5

    Gary 86 K5 1/2 ton status

    Joined:
    Oct 7, 2002
    Posts:
    204
    Likes Received:
    0
    Location:
    Mentor, OH
    For starters, I did a search and read a ton of info. Here's the deal, I just got completely done with my 4 spring 4" Rough Country lift and I have a bad vibration. It seems to be the worst around 25 mph and then it comes back around 50 mph. I haven't gone any faster than 50 because its pretty bad. What should be the first thing I do, change both rear u joints? drop the transfer case? I know its related to the lift cuz it wasn't there before. Does anyone have any pics of the t-case drop cuz I have no clue what to do.

    One other problem it has is that the front end seems very unstable over bumps, should I disconnect the front sway bar?? Thanks for any help guys!!! /forums/images/graemlins/cool.gif /forums/images/graemlins/k5.gif
     
  2. SpaceK5

    SpaceK5 Newbie

    Joined:
    Apr 5, 2002
    Posts:
    3
    Likes Received:
    0
    Location:
    Midland, Michigan USA
    I also installed a 4 Inch 4 sping Rc lift. I droped the t-case but i still have some low speed viberations. I calculated my driveline angles and found a 4 degree difference between the pinion yoke and the t-case yoke. I need to get new shims that are 2 degrees or more than whats allready on there. I think rough country designed this lift for longer wheel base vehicals like pickups so the shims that are included aren't at a high enough angle.
     
  3. Gary 86 K5

    Gary 86 K5 1/2 ton status

    Joined:
    Oct 7, 2002
    Posts:
    204
    Likes Received:
    0
    Location:
    Mentor, OH
    whats involved in dropping the t-case, i dont understand what to do exactly, is it just putting spacers on the crossmember bolts?? /forums/images/graemlins/cool.gif /forums/images/graemlins/k5.gif
     
  4. Gary 86 K5

    Gary 86 K5 1/2 ton status

    Joined:
    Oct 7, 2002
    Posts:
    204
    Likes Received:
    0
    Location:
    Mentor, OH
    anyone??? /forums/images/graemlins/k5.gif
     
  5. tori89k5

    tori89k5 1/2 ton status

    Joined:
    Apr 12, 2001
    Posts:
    946
    Likes Received:
    0
    Location:
    Pismo Beach, California
    Yep, thats all there is to it. From the factory GM uses some round spacers that are on the bolts, on top of the frame. Just do one side at a time, Take two bolts out on one side, remove the spacers from their current location, and install them between the frame and the crossmember, then do the other side. Here is a pic of the spacers, and the 1/4" bigger and much more stable spacer i made. The factory spacers allow flex because they have such small contact points to the frame. Thats why i built something big, flat and stable. [​IMG] [​IMG]
    This larger spacer almost totally eliminated all the vibes i got when i did my 14 bolt axle swap.
     
  6. Gary 86 K5

    Gary 86 K5 1/2 ton status

    Joined:
    Oct 7, 2002
    Posts:
    204
    Likes Received:
    0
    Location:
    Mentor, OH
    cool, thats what i thought, looks like ill start off doing that and new u joints and go from there /forums/images/graemlins/cool.gif /forums/images/graemlins/k5.gif
     
  7. Skigirl

    Skigirl 1/2 ton status

    Joined:
    Apr 2, 2001
    Posts:
    2,563
    Likes Received:
    0
    Location:
    Los Angeles, California
    </font><blockquote><font class="small">In reply to:</font><hr />
    I calculated my driveline angles and found a 4 degree difference between the pinion yoke and the t-case yoke

    [/ QUOTE ] Well, here's a stupid question... how do you do that?
     
  8. NITRO

    NITRO 1/2 ton status

    Joined:
    Jan 9, 2002
    Posts:
    1,057
    Likes Received:
    0
    Location:
    Frankfort In
    very carefully /forums/images/graemlins/tongue.gif

    NITRO
     
  9. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    Hehe that Nito being a smart A$$. LOL.
    You can pick up a cheap angle gage. it's just a wieghted dial that tells the angle something is at in relation to true vertical. Park the truck on level gound and the best thing to do is put the gage against the face of the yokes. Then a little simple math to figure out the difference.
    The ideal settings would be the pinion should be point up the same amount of degrees that the transmission is pointed down. Most will take 1 degree out of the pinion angle to alow for the tendancy of the pinion to climb the ring gear when under power.
    Thats how I set my pinion angle and I run down the road vibration free with 6 inches of lift on the rear. My case is not lowered. Now I know this should work fine for Skigirl because I know her truck is like mine and has a fixed yoke output on her transfer case.
    This doesn't always work on a 208/241 equipped truck because the slip yoke tends to bind when the angels are far less sever than I'm running. A CV rear drive shaft would be advised on anything over 4 inches from stock. Stock mean go find a stock truck and measure. Many lift spring may advertise 4 inches but are really closer to 5 maybe even more. My 2.5 inch Rancho front springs are 3.75 over my wifes stock 79. With a 2.5 degree shim I use to run when I was still full time they were a full 4 inches over stocl as measured from top of axle tube to bottom of frame.
     
  10. Skigirl

    Skigirl 1/2 ton status

    Joined:
    Apr 2, 2001
    Posts:
    2,563
    Likes Received:
    0
    Location:
    Los Angeles, California
    Thank you Grimmy. Started to notice vibration accelerating up to about 25-30mph, then goes away (not under load anymore). Happened after I had the rear blocks removed, along with broken springs and had new lift springs put in. No more saggy butt, so angle is different. Anyway, thanks again! /forums/images/graemlins/thumb.gif

    Nitro: /forums/images/graemlins/smirk.gif LOL
     

Share This Page