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, not good.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by txguy, Oct 17, 2001.

  1. txguy

    txguy 1/2 ton status

    Joined:
    Sep 4, 2001
    Posts:
    114
    Likes Received:
    0
    Location:
    Round Rock (Austin) Tx
    I think this may have started a day or two ago, and now its very noticable. Overall vibration throughout the cab. Doesn't seem to be coming from a particular place. Steering wheel is receiving some of it, but seems to be less than the cab, or at least the noise being created in the cab. It most harsh between 25ish to 40ish MPH. Lower than that, don't notice anything. Higher than that it is still there, but the amplitude lessens as speed increases. I have ran the auto tranny through the gears manually to give varying RPMs. Does not seem to change behavior. The vibration frequency increases as the speed does. The kicker is, when I let off the gas, it stops completely, and when I get back on it, it starts again. HELP!!! If I floor it from say 30, and it loads things up, it doesn't make it worse... Anyone??? And, there does not seem to be any difference if I am going up a hill, down, or on level ground. If there is, it is not much. This is in 2hi. I have tried it in 4 hi, hubs free, no difference. Have not had a chance to engage the hubs, or try it in low.
     
  2. Tybee

    Tybee 1/2 ton status

    Joined:
    Mar 25, 2001
    Posts:
    1,565
    Likes Received:
    0
    Location:
    Centennial, CO
    I had the same problem and symtoms as you and it ended up being the u-joints even though there was no play in them at all, good luck finding the problem.


    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  3. when my k5 decided to spit the rear u-joint, i started getting a vibration that would rattle my center console..... it got progressively worse, and the driveshaft went out, bashing the exhaust and floorboard, at least it didn't crack the tailshaft...

    is it a high-frequency vibe, unlike a tire vibe ( the difference you can definitely tell..)?? so it happens under load, huh??

    change those u-joints!! they're cheap, the d-shaft and tailhousing isin't....ain't....aren't///....

    greg ( good luck!!)
     
  4. Sparky

    Sparky 1/2 ton status

    Joined:
    Aug 20, 2000
    Posts:
    423
    Likes Received:
    0
    Location:
    San Antonio(summer) Texas A and M (school year)
    Sounds like you have a classic case of a bad U-joint. Very common on blazers, and not too big of a deal. To test it... get under the truck with it in neutral and the e break on. Grab the rear drive shaft and look/feel for any play in the u-joints as you turn it. Note: dont confuse play in the joints with play in the transfer case/yoke. If you dont see/feel anything i would still pull the driveshaft off and CAREFULLY pull the bearing caps off the u-joints. Inspect the needle bearings. If they fall out all over the place it is most likely out of grease and needs to be replaced. If it does not have any needle bearings the pivot points are worn out it needs replaced. If the needle bearings stay in place and are well greased your vibration is from something else. To replace the u-joints get a big vice and a socket bigger than the bearing cap on one side and a socket smaller on the other side. Press the u-joint untill the bearing caps fall out then remove the joint and press new u-joints in. Once you get good at it, it only takes about 20min. or so to do. Good luck

    When all else fails... Check the blinker fluid.
    78 K-5
     
  5. txguy

    txguy 1/2 ton status

    Joined:
    Sep 4, 2001
    Posts:
    114
    Likes Received:
    0
    Location:
    Round Rock (Austin) Tx
    Thanks guys!!! I had it inspected by a 4x shop about a month ago right after I bought it, they said both the U-joints needed replaced. I will pick some up on the way home. I was hoping that was the problem
     
  6. txguy

    txguy 1/2 ton status

    Joined:
    Sep 4, 2001
    Posts:
    114
    Likes Received:
    0
    Location:
    Round Rock (Austin) Tx
    Ok, pulled the drive shaft... The U-V joint on the rear is done, however the one that is on the transfer case looks like it may be slightly different. Anyone know if it is???
     

Share This Page