Odd noise coming from drive train.

Discussion in 'Chevy Express Forum (GMC Savana)' started by dave3500, Nov 8, 2013.

  1. dave3500

    dave3500 New Member

    I have a 2000 Express 3500. 180,000 miles tranny replaced about 20k ago. It recently developed an odd condition... during the 1st 10 min of driving it will make a deep knock somewhere behind me in the drive train. It doesnt happen often but it usually will happen at parking lot speed or around 45 mph. I also noticed it when turning a sharp right in the parking lot. It all seems to go away after about 10-15 min of driving.

    I checked the u-joints for play
    I checked my differential fluid and it seems fine.
    I have had a bad spark plug on a ford truck do something similar but this hesitation or knock is very irregular and the ford did it constantly.
    I have purchased new plugs and wires but am waiting to dive into that project till I do a bit more research.
    I left it parked since I noticed the issue because if its a tranny or other issue i dont want to make it worse.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    did you ever figure this out? could just need the slip yoke greased. drop the drive shaft, lube the slip yoke up real good, inside and out, then reinstall. when mine needs lubed it is more of a high pitched "clank". is it a continuous knock or just one time? I know that when the rear carrier bearings start to go out they will make a knock when you load one side (turn left or right)
  3. BurbanMan

    BurbanMan Rockstar 3 Years 500 Posts

    Does it do it when turning only or also when going straight?

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