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2003 Suburban 4WD clicks when engaged

Discussion in 'GM Powertrain' started by POSCamaro, Dec 27, 2010.

  1. POSCamaro

    POSCamaro New Member

    I have a 2003 Suburban that clicks when the 4WD is engaged. I just put it in Auto 4WD and drove through a snowbank for fun. It thunked going into 4WD and continuously clicked when in 4WD. When in 4Hi it thunked while engaged and thunked on a regular basis while engaged.
    Any assistance will be appreciated.
  2. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    Sounds like a bad U-joint on the Front Driveshaft, or else the transfercase... id start with the U-joints on the front driveshaft however.. Also a CV axle can clunk to dpeending on how bad it is but it would have shown more signes before this.
  3. POSCamaro

    POSCamaro New Member

    Someone hit the driver's side front bumper and fender while I was deployed. I'm afraid that the damage is not cosmetic, possibly only the CV joint.
    What do I look for the repair the u-joint / CV joint? I'm going to assume CV joint if the front tire was also hit. The front transfer case maybe suspect also?
  4. murdog94

    murdog94 New Member 1000 Posts 100 Posts

    Well the CV joint should have a good boot on it and if not then right there that shows some of the issue. And for U-joints check for play in the driveshaft.. and the front differential is doubtful, the transfercase is the more common on the problems.
  5. POSCamaro

    POSCamaro New Member

    I'm afraid for what may have gone wrong from being hit. Is there any way that the hub could have been damaged from the accident. I'm hoping for easy and cheap.
  6. POSCamaro

    POSCamaro New Member

    I finally got under the truck. The connector to the motor that engages the 4wd had rubbed on the front drive shaft and almost wore through. I cut out the bad part and spliced the connection. It no longer thumps when engaging 4wd. It does, however make a thunk / popping noise once in a while when using 4wd. I used it in the lawn after repairing the bad wire (6" of snow should allow the truck to slip if needed). Any ideas what that noise could be?
  7. garth stuart

    garth stuart New Member

    Could be a loose chain in the transfer case. if you start on a road that has some ice or snow on it and you hammer on the throttle and you hear this thunk/popping noise from somewhere below you then it could be the transfer case drive chain.
  8. POSCamaro

    POSCamaro New Member

    Figured it out. The oil pump in the transfer case wore 2 small holes through the case. Required transfer case replacement to fix.

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