Clunk at take off.

Discussion in 'GM Powertrain' started by RVJ, Dec 22, 2007.

  1. RVJ

    RVJ Rockstar 100 Posts

    When I bought the truck there was no noise. After 1 week I would notice a clunking noise when pulling away from a dead stop about 10 percent of the time. I took it to dealer and he couldn't replicate the noise, but then he only test drove it around the lot. In the last week it has gotten worse and shows up more often and even when it shifts from 1st to 2nd and only about 20 percent of the time. I'd like to take it back to them but I almost think they are trying not to find it till after the warranty is up. Anybody have any thoughts or advice? Thanks in advance.
  2. TahoeFever

    TahoeFever Epic Member 5+ Years 500 Posts

    check the usual fluids etc etc ..but i had the same thing ended up going to another stealership since the first one told me i was nuts so i went to a smaller dealership family owned and amazingly they were able to diagnose the problem and they ended up swapping the tranny they found it was slipping gears ..

    good luck :)
  3. RVJ

    RVJ Rockstar 100 Posts

    Thanks, that's what I was contemplating doing. I would hate to do unneccessary damage to anything.
  4. ChevyFan

    ChevyFan The Sheriff Staff Member 5+ Years 1000 Posts

    These sorts of noises can occur and are sometime common. Not always though. Is it still under warranty?
  5. RVJ

    RVJ Rockstar 100 Posts

    The truck has 35,900 miles on it. It was GM certified which gives me another 3000 miles of warranty and I made sure it came with 5 year/100000mile warranty also. The dealer said he couldn't replicate the noise but according to my trip meter he test drove it for less than 1 mile. It feels like the rear end is shifting back and forth or the tranny is moving. It doesn't feel like an internal problem. If it's normal then I can live with it but If it's moving around I have to believe it's causing damage. The 99 Sierra I traded for the 05 had 116000 miles on it and it made absolutely no noise whatsoever. It sounded more solid and I guess I'm just paranoid that it's going to cost me a bunch of money I don't have.
  6. homer911

    homer911 Rockstar 100 Posts

    My Dad had a 01 that did the same thing. After takeing to the dealer 3 times they finally told him that it is normal and that there is nothing that they can do. To me it sounded a little funny that they found the problem but could do nothing to fix it. If i remember correctly it it something in the trans. I am not sure though. Like the shift soliniods.
  7. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    The first thing I'd check for a clunk on take off would be the u-joints.
  8. RVJ

    RVJ Rockstar 100 Posts

    I had it over a pit yesterday with me in the pit and a friend rocking forward and back. It's almost what I would think in the rearend as it tilts up and down which makes the leaf springs close and open. The U joints feel tight and when I twist the driveline back and forth I can hear it go tink in the aluminum drive shaft. The tail shaft in the tranny moves in and out a little while rocking it also. Nothing appears loose and moving. The spacers inbetween the leaves are present, I was hoping the were gone. I read somewhere that a helper spring would stiffen the movement up but I'm really at a loss here.
  9. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    Any movement in the pinion bearing? You've kind of associated the noise with the axle wrap, so I'm wondering if it's in the pinion bearing.

    For that matter, where you've associated the clunk with axle wrap, how are the suspension connections? Any loose shock bolts or worn sway bar bushings or similar?

    Which direction is the movement at the transmission: in an out or up and down? Just for clarification, does this mean it's a 2wd, or is it a 4wd as indicated in your signature (in which case we are actually referring to the transfer case)? If it's a 4wd, which t-case, and does the noise change at all from 2wd to any 4wd positions?

    The driveshaft on my Suburban doesn't have one, but does yours have a slip yoke that could be making the noise?

    Rear disk or drum brakes? Anything sticky in the rear brakes that might cause them to hang up sometimes and cause a clunk? Do you regularly use the parking brake?

    Just brainstorming ideas, I'll try to post more if I think of any.
  10. RVJ

    RVJ Rockstar 100 Posts

    Some of my terminology mave be off but I'll do my best.

    The spring U bolts appear to be tight, as well as the shock bolts.
    The movement I called in the transmission tailpiece is actually where the driveshaft is attached to at the front of the dshaft. It is 4Wd so I guess I mean the transfer case. When the truck is rocked forward and backward the spot where the front of the driveshaft attaches is moving slightly in and out, may be normal???????
    When rocking it the front of the rear end is slightly changing the angle in whech it points if you would consider the attachment point as the pointer, it points up the down slightly as the truck rocks back and forth.
    As the truck rocks or when I turn the Dshaft back and forth manually I can hear and feel a clang or slop in the system somewhere, it almost feels like it is in the dshaft itself.
    I don't know what a sway bar bushing is.
    I've only used 4wd briefly and only to get the truck out of the deep snow and never noticed it for sure. It's getting more frequent the more I drive it.
    I'm not sure what a slip yoke is.
    I believe it has rear drums and I've never used the parking brake.
    Hope this helps in the diagnosis.

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