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newbie help 700r4 leak question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by deucestroke, Jan 14, 2007.

  1. deucestroke

    deucestroke Registered Member

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    '86 k5 350/700r4/np208 I have a leak where my transfer case mounts to the tranny. I dropped the case and think its comming from the rear shaft seal on the tranny. I've never messed with a tranny before but looks like the only way to get to it is to drop the pan and go from the inside.Any help appreciated. thanks
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    There is no seal on the tailshaft of a 4x4 trans. If it is leaking between the t-case adapter and the tranny replace the O-ring and the leak should stop. Inspect the t-case adapter for any cracks when you have it off as that is another common area to cause a leak if it is cracked.
     
  3. deucestroke

    deucestroke Registered Member

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    thanks for the help.It's actually leaking past the gasket at the front of the t-case and rear of tranny no o-ring. Does the tranny and the t-case share common fluid?
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Both the tranny and the t-case use ATF but they are not connected to each other. There is an input seal on the t-case that keeps tranny fluid from enter it and over filling the t-case. Check your t-case level to make sure it isn't over full. If it is then the input seal has gone bad and that needs replacing. There is no seal between the adapter and the t--case, only silicone sealer. The front side of the adapter between the adapter and the tranny is supposed to have a large O-ring.
     
  5. deucestroke

    deucestroke Registered Member

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    I droped my t-case and there was a gasket between the adaptor and t-case.thats right where the slow but steady leak was coming from
    the seal in the t-case looks new. the guy I got my to good to pass up
    "free" 86 blazer did a little half assed work and the gasket had some silicone on it
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    If it is still leaking then get rid of the gasket and put ultra black silicone and be done with it. I use about a 3/8" wide bead of t and when you get to the bolt holes go around the holes so there is no way it will ever leak again.
     
  7. deucestroke

    deucestroke Registered Member

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    how much atf is there suppost to be in the end of the tranny I see a hole in there on the bottom. is that a drain hole back to the pan?
     
  8. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Tranny fluid will drain back through the hole you see back into the pan.
     
  9. deucestroke

    deucestroke Registered Member

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    Thanks I appreciate all your help.
     

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