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NP-205 T Case Leaking Bad

Discussion in 'The Garage' started by ks2krpt, May 23, 2005.

  1. ks2krpt

    ks2krpt Registered Member

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    My friend stopped by today with a 91 K5 he just bought. The NP-205 was leaking oil past the seals on the output shafts and also the Speedometer connection. I pulled the oil level plug to see how low the T case was. When I pulled the Plug, you could hear a loud Psssst. The T case was under presure.

    I looked further and found that on top of the case about over the rear output was a steel hose fitting that someone had put a rubber cap and hose clamp to hold the puch on cap in place. No wonder it was under presure.

    My question is; what goes on that steel hose fitting ? Is it just a length of hose held up in the air, or is there some type of check valve that goes in the end of the hose.

    Is there any seal in the speedo port on a NP-205, it was really leaking bad from there.

    What weight oil is recomended for the Np-205

    Thanks for the help

    Paul
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    If it's got a hose fitting, it originally had a short section of hose, with a plastic breather cap on it, just like the front and rear diff breathers. Some are just a metal breather cap.

    What year is the 205? I *believe* that the housing changed from unthreaded to threaded for the driven speedometer gear "sleeve" at some point. I've got an unthreaded housing in the garage, but I haven't had a "newer" one apart to see how it's held in place.

    80W90 for the older cases, Dexron was specced in the 80's, I'm going with 80W90 anyways.
     
  3. ks2krpt

    ks2krpt Registered Member

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    Np-205, 1993

    Thanks for the reply. My friends believes the NP-205 to be a 1993. His truck is sort of a bunch of parts made into something for off road. The Speedo connection is threaded.

    Do you agree with the breather port capped and building presure in the T case, the leaks around the seals and speedo port would be expected ?

    Paul
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Yep. Front diff did the same thing with a plugged breather. Also when the case overfills from fluid (bad tranny to t-case adapter) it will start spitting it out around the outputs, but mine didn't leak from the actual gaskets or even the vent.

    1993 205 isn't going to be GM, I *think* Dodge was using the 205 that late, but I believe they would have been the only ones. It sounds like a 205 from your description though. (iron case would cement that or a 203)
     
  5. ks2krpt

    ks2krpt Registered Member

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    Np-205

    Yup, cast iron case, for sure Np-205

    Paul
     

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