1990 chevy Cheyenne 4wd

Discussion in 'Chevy Truck Forum' started by Randy2112, Jan 7, 2017.

  1. Randy2112

    Randy2112 Member

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    Ok I have looked at hundreds of forums to find my answers and I cannot find it.
    I have a 1990 chevy Cheyenne automatic converted from a manual. Have no idea why the changed it but hey for some reason they did. Anyways my 4wd worked when I bought it and now it won't engage. The light use to come on in the floor board and everything now nothing when in 4hi or low. I placed my phone on the ground while engulfed and the drive shaft to the front diff is spinning. I have power at the front actuator 14 volts and I took the actuator out plugged it in and when in 4wd the plunged comes out but not really that far. Changed the actuator out for one out of a parts truck same thing. If I push against it it has resistance and stays out. I manually put the end of a screw driver into the diff and the leaver would only move prob half an inch just guessing tho. Put it back in still no lights on the floor board and I have a bunch of snow right now to I put my front tires in deep snow put it in 4wd and only the back is spinng? So it's not engaging but with everything I have tried seems like it should be. Oh and I have no 4wd fuse anywhere the only fuse box I can find is under the dash driver side. Any help would be greatly appreciated. My next step I'm going to do is jack up the front end engage the 4wd and see if the tires move. Any thoughts?
     
  2. Randy2112

    Randy2112 Member

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  3. leolkfrm

    leolkfrm Full Member

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    check the ball switch on transfer case, the actuator/and light gets its ground thru it , you can unlug it and jump it, if it works and you have trouble getting it to work in the proper manor, put a switch in it attached to shifter housing
     
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  4. Randy2112

    Randy2112 Member

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    Where is the ball switch?
    And is it just a two wire switch that you jumper out?
     
  5. kbrown11

    kbrown11 Full Member

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    the switch sits on top of the transfer case just above the shift linkage on the driverside. some have two wires, newer ones have three. you can use an adjustable wrench and take it off and see if the ball is not stuck due to rust or dirt.
     
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  6. Randy2112

    Randy2112 Member

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    Update..
    I jacked the front left tire off the ground and removed the front actuator and stuck a screwdriver in to manually engage the front dif and the tire wouldn't lock in. Checked the ball switch and everything was good.
     
  7. Randy2112

    Randy2112 Member

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    So I'm assuming it needs to be replaced or rebuilt. Right?
     
  8. kbrown11

    kbrown11 Full Member

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    I agree with you Randy, if you are not able to manually engage the front differential, there is a problem inside the front differential.
     
  9. Kennyray

    Kennyray Moderator
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    I think you would have to have both wheels off the ground because the front dif is open.
     
  10. Randy2112

    Randy2112 Member

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