Possible U-joint Problem

Discussion in 'GM Powertrain' started by MTM, Dec 29, 2011.

  1. MTM

    MTM Rockstar ROTM Winner 100 Posts

    How to know if I have bad u-joints?
  2. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    The old tried and true method is to put the truck in park or first gear if its a manual trans, put the parking/emergency brake on, climb under and grab the driveshaft and try to turn it.
    There should be a slight wiggle from the driveshaft while trying to move clockwise or counter clockwise, the gears taking up slack, but if you have any movement between the driveshaft and the yoke this means you've got bad U-joints. Check both ends, at the trans and at the pinion.
    Normally if I replace one set I go ahead and do the second set also, just easier to replace all at once rather than have to get under the truck a few weeks or days later to do the other end (which is what happens if you dont do both at the same time).
    If you've got a carrier bearing make sure you check for excessive play there too.
    Last edited: Dec 29, 2011
  3. TRPLXL2

    TRPLXL2 Epic Member 5+ Years 1000 Posts

    When my U joint went bad in the back by the rear axle on my s10, I could hear a clunk when the truck was put into reverse. There was also a slight driveline vibration that could be felt through the floor board, If you have the stock u joints and carrier bearing I feel for ya!! We pressed off the carrier bearing which was also bad, and our 20 ton press barely pressed it off! Those nylon keepers on the ujoints those are fun too, then again I an a girl..........
  4. MTM

    MTM Rockstar ROTM Winner 100 Posts

    Okay i will try that tomorrow.Sounds like a good cheap way of trying it. It's a weird sound. I put it on a lift and put it in gear and it doesn't make the noise so it only does it when it has pressure/strain on it.
  5. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    just roll at 10-15mph and give it a good stab and let off the gas, you will here a metal on metal clank from underneath. Or if they are bad enough you will see the needle bearings sticking out of the u-joint
  6. MTM

    MTM Rockstar ROTM Winner 100 Posts

    Tried all the trick same thing.not sure if it's the problem
  7. wildmans92

    wildmans92 Member

    hat kind of noise are you hearing because u'joint can squeak too then the only way to find that problem is to drop the drive shaft if you cant move the u joints by hand then your needled bearings are locked up and you need to replace the u joint.

    Good luck,
  8. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Just curious here, Are you getting a thumping or clunking noise from the rear?
    If your truck has a slip joint on the driveshaft there should be a zert fitting, try greasing it up enough so grease starts oozing out the slip joint and see if that doesnt cure your noise.
  9. MTM

    MTM Rockstar ROTM Winner 100 Posts

    It's just a weird squeak noise it's hard to explain. Starts a about 15 mph and stays at a constant tone doesn't get faster when I accelerate
  10. GM-Guy

    GM-Guy New Member

    Ujoints don't have to have play, to be bad
    When the dry out [usually squeek] they create a "arthritis" type of condition, meaing the joint cannot rotate properly and causing balance/vibration issues
    The only to know for sure is to pull apart and feel them, like stated above

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