Is there something bent in my drive line?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Fine Burban, Nov 3, 2013.

  1. Fine Burban

    Fine Burban New Member

    I noticed last night on the drive home that when going 30 MPH and giving it maintenance throttle that it seems as if the Driver side rear (may be passenger as well) moves up and down to give it a bouncing feel, but as soon as I let off the throttle it goes away completely. @30MPH I am in 3rd gear on a 700R4 Trans. Any ideas would be greatly appriciated.
  2. summitwhite11

    summitwhite11 New Member

    I normally look to u-joints and carrier first, curious, off road or street driving .
  3. Fine Burban

    Fine Burban New Member

    Street driving, but I have only owned the truck for about a month now and still finding issues with it. I checked the U-joints this past weekend for slop or excessive wear. I didnt really see anny but I will be replacing them soon when time and money is available. Thanks for the input, maybe I just over looked something.
  4. BurbanMan

    BurbanMan Member

    I originally though about wheel/tire/shaft balance but then I read that it stops when you get off the throttle.
  5. Fine Burban

    Fine Burban New Member


    Yeah that is what I was thinking as well but it legitimatly feels as if the back end of the travels 1.5-2" up and down when maintaining speed arounf 30 MPH and 15 MPH since those are the the 2 speed limits on my way to and from work.
  6. summitwhite11

    summitwhite11 New Member

    Thinkin it would be worth swappin one tire/wheel at a time on the rear to prove there is no tread seperation or related wheel issues, its going to be a process of elimination anyway, balance is normally a vibration that will increase with speed,tread seperation will deliver vibration and or bounce.
  7. Fine Burban

    Fine Burban New Member

    I will experiment this weekend since I dont think I will have time durring the week to try that so I will keep this thread updated. Thanks for the idea.
  8. j cat

    j cat Active Member

    with the axles free to rotate check for bad bearings and axle U joints. check pinion bearing at the rear diff. check for rear wheel bearings to be tight also if bad these usually leak.
  9. Fine Burban

    Fine Burban New Member

    I just replaced the rear shoes and hardware kits in the drums and didnt notice any excessive play in either axle but I did not look at the pinion gear bearing.
  10. BurbanMan

    BurbanMan Member

    if the tread were separating, he should be feeling that at all speeds. Week at first and more violent as speed increases. SHOULD being the key word lol
  11. summitwhite11

    summitwhite11 New Member

    It prolly is not tread seperation, I only tossed that in as a chevy buddy of mine ran across one of those cant pass it up deals on a 1 ton Dodge truck, a few months into owning it the front end started feeling like he was on wash boards on the front between 40 and 55 mph, A guy at work told him to swap the front tires to the rear, and the bounce shifted from front to rear, one tire was the culprit, two new tires she was smooth sailing again. This was a couple of years ago. I agree, could be a number of things, just have to trouble shoot down the list till you arrive at the auh haaaaa moment..
  12. mfleetwood

    mfleetwood Moderator

    A quick check might be to take a look at where the drive shaft weights are and see if any have fallen off (you'd notice a clean(er) rectangle/square pattern of where it may have fallen off from). I lost one of my weights, which caused the vibration only occur at higher speeds but I can't remember or noticed if acceleration or deceleration had made it worse or better. In any case, this one is not too much trouble or takes a lot of time to look at.

    Good luck!
  13. bazar01

    bazar01 New Member

    Can you get somebody to follow your Burb while doing 30mph to look at how the rear tires look when it bounces that much? I think this is a tire issue.
  14. Fine Burban

    Fine Burban New Member

    The only issue that I have with it being a tire issue is that it only happens under maintenance throttle and it does not get any worse until I reach 58 MPH thru 70 MPH. I know that is a balance issue though. I dont get to test higher speeds because the freeway is about 45 mins from where I live. I would imagine that the tread separation / vibration would increase at speed. At 40 MPH I do not notice it as much. I am going to look into the Pinion gear play and see what I can find. Maybe tomorrow morning I will post up more info as to what I find. Now would it be a transmission issue? My gut is telling me no but when in 3rd gear it happens but when I put it in second gear I cant feel it. I will have the woman ride with me tomorrow and see if she feels it in 2nd gear.
  15. Pikey

    Pikey Moderator

    I agree! if it just came out of nowhere look for thrown weights. Also, check the rear pinion flange, where the yoke for your drive shaft bolts to the rear end. There should be a weight there.

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