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Transmission fluid in Transfer case?

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by dr1553, Sep 12, 2001.

  1. dr1553

    dr1553 Registered Member

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    Everyone,

    I just started rebuilding my NP205. Its full of transmission fluid. Why? Do some people put transmission fluid into transfer cases?

    I dont know for sure but I would imagine the case would take 75w-90 gear oil and not transmission fluid.

    Later,
    David
     
  2. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    I don't know about the 205. But the 208 does take tranny fluid...Dan

    If it ain't broke.......Don't fix it....
    <a target="_blank" href=http://coloradok5.com/gallery/Gokartergo>KLICK</a>
     
  3. Steve_Chin

    Steve_Chin 1/2 ton status

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    The NP205 is supposed to use cat pee (gear oil). ATF contamination of the transfer case oil is likely due to a bad seal in the transfer case adapter. If you replace the seal, all should be well. Another measure you can take for added insurance is to install a sealed bearing at the input of the transfer case. A Nachi 6307NSE (or equivalent) fits perfect.
     
  4. dr1553

    dr1553 Registered Member

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    Steve,

    Is that the first bearing that you see when you look at the end of the adapter? Will a sealed bearing last as long as the regular open bearing that is always getting new lubricant?

    Where can I get Nachi bearings?

    I dont know if there is a bad seal is the adapter of if someone just put tranny fluid in it. I'm about to take the adapter apart right now. The stuff inside looks like mostly transmission fluid mixed with a little gear oil.

    Thanks,
    David R.
     
  5. Steve_Chin

    Steve_Chin 1/2 ton status

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    dr1553, it's the bearing that's at the front of the transfer case. It supports the input shaft. The sealed bearing will last just as long, maybe longer because it is greased permanently.

    You don't have to get a Nachi brand bearing, just get one that crosses to it. Look in the phone book under "bearings" and you should find a bearing distributor near you. King Bearing and Motion Industries are two of the larger national distributors. If you can't find a bearing house near you, Advance Adapters sells that bearing as part of their NV4500 conversion kit and you might be able to purchase the bearing alone from them.
     
  6. JUNKYARDJOHN

    JUNKYARDJOHN Registered Member

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    I JUST FINISHED PUTTING SEALS &amp; GASKETS IN MY 205 FRI. THE NP205 TAKES 90 WT. GEAR OIL. THERE ARE TWO SEALS IN THE ADAPTER (ONE AT EACH END) ONE TO KEEP THE ATF FLUID IN YOUR TRANNY, &amp; ONE TO KEEP THE GEAR OIL IN THE T-CASE.
     
  7. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    Put good seals in the adapter and you should be fine. The sealed bearing might help too. I used cheapos first, then filled the 205 with atf to the point that it blew out the rear output seal going down the road. Then I went to the dealership and got good seals.
    Really there isn't anything wrong with ATF in the 205, it was spec'd for later model trucks, and didn't seem to hurt them, but 80-90 is better I think. Maybe just because it's the "old good stuff". Anyway, don't be concerned about damage because of the ATF.

    Making the world better, one truck at a time.
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  8. Triaged

    Triaged 1/2 ton status

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    I thought I would bump this one back up to the top insted of starting a new one. I will try and find that bearing that Steve_Chin posted....

    What are the part #'s for the seals in the adapter (th350/np205)?
     
  9. down4thakrown

    down4thakrown 1/2 ton status Premium Member GMOTM Winner

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    the 2 seals one the adapter are they like an o'ring or a paper gasket??Im about to do the seals in my 205? I bought a gasket kit from 4 wheelers and it didn't come with the oring for the adapet to tranny side. Does the adapter to tcase side take take the same oring or is it a gasket type??Where can i get these seals??
     
  10. Triaged

    Triaged 1/2 ton status

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    I am sure the seals are regular steel/rubber lip type seals. There is one to keep the trany fluid in the tranny and one to keep the gear oil in the t-case. There are also 2 bearings in the adapter that hold the spud shaft. If you are going so far as to reseal the whole thing make sure you replace the spud shaft as well.
     
  11. sponsoredbydad

    sponsoredbydad Dune Slaying Sand Junkie Premium Member GMOTM Winner

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    Been there had that problem. to confirm seal leak check the level at the fill hole if it pours out the seal is gone. if it is at normal level somebody messed up. mine started flowing out the breather on to and all over the rear tailgate &amp; window /forums/images/graemlins/yikes.gif
     

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