Bad vibration from 25-80mph

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by texas99lb, Sep 4, 2009.

  1. texas99lb

    texas99lb Rockstar

    Hey people..I have been experiencing a vibration when taking off from 25 and so on...I am leaning towards an enigne/trans mount, because the vibration will go away when taking my foot off the gas...The vibrations is enough to rattle change in my console and shake my steering wheel...any suggestions???

    Also Does anyone know if I can get an oem drivers side rear brake line pre made, or do i have to make my own..mine is starting to leak and I am using quite a bit of brake fluid..

    I searched to find the answer to this question, but to no avail..When coming to a stop, or taking off from a slow roll, I will get a loud noise coming from the rear end...its sounds like a hubcap rolling, I can not pin point where it is coming from, I was just wondering if any else has experienced this....

    Sorry for all the questions..I am just having some issues...thanks in advance for the help
  2. dano8928

    dano8928 Member

    How many miles do you have on this beast? youve got a hell of alot of problems! haha. I have a '99 silverado with 170,000 miles and dont have NEAR as many problems as you.
  3. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Sounds like two problems to me. Rusted brake line. Easy to bend your own, very foolish to keep driving this truck without it fixed. As for the vibrations, start by checking your u-joints.
  4. texas99lb

    texas99lb Rockstar

    I only drive it when the resovoir is full of fluid..and on short trips, other than that it is parked...I have 182,000 miles on it...The PO used the truck as an oil rig truck, so it was put through some abuse..It runs great and gets the job done...Yeah I was just going to go make my own brake line, but I wasnt sure if there was a oem replacement piece I could buy for ease of installation..Are driveshaft u-joints difficult to replace. I have never replaced them before. Thanks
  5. DOOGY

    DOOGY New Member

    sounds like drive line...have you had the truck lifted or lowered? Differentials must be in proper alignment...slightest tilt out of line can cause vibrations
  6. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I wonder if your noise is also the cause of your vibration. I would also check the ujoints. Search you tube for Gm u joint replacement. There are plenty of vids on it. Hope you have a torch!
  7. f5fstop

    f5fstop Former Member

    Might want to look at the mounts...

    #PIT3009M: Suspension Vibration Or Frame Beaming At 40-60 MPH (64-96km/h) - (Apr 28, 2011)

    Subject: Suspension Vibration Or Frame Beaming At 40-60 MPH (64-96 KM/H)

    Models: 1999-2011 Chevrolet Silverado and Silverado Classic

    1999-2011 GMC Sierra and Sierra Classic


    This PI was superseded to update model years. Please discard PIT3009L.


    The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

    Beam shake vibration is usually felt in the seat and occurring at speeds between 40-60 mph (64 - 96 km/h). Hertz readings using an EVA tool are normally between 8-24 Hz. This condition is most common on extended cab and crew cab models but has also been noted in other models.

    The severity of beam shake may vary from vehicle to vehicle. To determine if the concern is beam shake, please perform the following

    •Test drive vehicle to confirm the condition. A beam shake condition will usually respond to concrete type pavements more than asphalt, so the vehicle should be driven over both surfaces if possible.
    •Place 200-500 pounds in the pickup bed between the closed tailgate and the wheel wells. The beaming condition should dissipate.
    Note: Tires with excessive Radial Force Variation (RFV) or out-of-roundness can intensify the frame beaming concern. The following radial force variation numbers should be used as a guide:

    P-Metric tires (2wd 1500): 12 lbs or less

    P-Metric tires (all others): 24 lbs or less

    LT-tires: 30 lbs or less

    If the concern is determined to be beam shake, this is a characteristic of the vehicle. GM Engineering has released updated body mounts to help reduce this concern for the Crew and Extended Cab Models. There will be no changes made to the Regular Cab Models.

    On 2009 and later models, many trucks are already built with the updated body mounts. Before replacing the body mount visually inspect the mounts to make sure they are the old style.

    The new upper and lower mounts should be installed at the left and right rear cab positions. Inspect the upper mounts in these positions and compare to the pictures below to help determine if they are the new or old style mounts:

    •If the upper mount is similar to the picture below (1), then this is the old style and the new mounts should be installed (Extended and Crew Cab Models Only). Follow the appropriate SI procedure for replacing the body mounts and torque to spec.
    Note: The new LOWER mount is a two piece design, meaning there is a rubber mount with a metal washer. Some models may use a one piece lower mount, meaning the rubber mount has a metal washer molded into it. If the vehicle has the one piece lower mount design, washers (PN 15854745, Qty 2) will be needed to be used with the new lower mount.

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    [TD="class: td2"]Click this bar to view the full image.[/TD]

    •If the upper mount is similar to the pictures below (2 and 3), then this is the NEW style mount and no further repairs should be performed.

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    [TD="class: td2"]Click this bar to view the full image.[/TD]

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    [TD="class: td1, width: 20"][​IMG][/TD]
    [TD="class: td2"]Click this bar to view the full image.[/TD]

    Parts Info

    Part # Description Qty

    25994881 Upper Mount 2

    25791032 Lower Mount 2

    15854745 (if needed) Washer 2

    Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

    GM bulletins are intended for use by professional technicians, NOT a ""do-it-yourselfer"". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
  8. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Great info! I would not blame your vibration on frame beaming until I eliminated ALL of the other possibilities, From a bent rim to a bad u-joint. I suspect that your "hubcap rolling" noise is you cause of your vibration
  9. James4012

    James4012 Member

    Sounds like U joints. I had a 93 that would pop when placed into gear and slight vibrations while driving so I removed the drive shaft and took the caps off the u joints. The stud was worn down and half the little rod bearings where shattered. All you really need to replace them is snap ring plyers, a 1/2 drive extension *what I used, it's about the right size for the u joints* a nice sized hammer and a solid place to place it to hammer it. Course that's the shade tree way. And if you don't know what you're doing it's every easy to bust one of the ears off the drive shaft rather than successfully knocking the u joint out.
  10. j cat

    j cat Epic Member 5+ Years 1000 Posts

    this post request is FY 2009 .

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