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NP203 from a Turbo 400 to a 350?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by SkyScraper, Aug 6, 2003.

  1. SkyScraper

    SkyScraper Registered Member

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    Hello all!

    Got a couple of transfer case compatablity questions.

    The Transfer case that I have (NP203) has a chain going out. /forums/images/graemlins/confused.gif My friend has an used NP203 case lying around at his house. He told me I could take it and have it rebuilt and put it in my truck and then give him back the old one out of mine. Which is a cool deal. Of course niether of us know if there are any major issues with the one he has. (He bought it from someone in this NG).

    The questions I have is my friends case came off a Turbo 400 and my Trans is a Turbo 350.

    1) Is there a spline difference between these 2 cases, since the trans are different?
    2) If so, would it be more expensive to make this case compatiable with a my 350 or should just get mine fixed and repaired?
    3) Maybe I can switch out components between my case and the other one to make his compatiable with my trans?

    Any suggestions? /forums/images/graemlins/1zhelp.gif

    TIA,
     
  2. azblazor

    azblazor 1/2 ton status Premium Member

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    [ QUOTE ]

    1) Is there a spline difference between these 2 cases, since the trans are different?

    [/ QUOTE ]
    TH350 output spline is 27
    TH400 output spline is 32

    [ QUOTE ]

    2) If so, would it be more expensive to make this case compatiable with a my 350 or should just get mine fixed and repaired?

    [/ QUOTE ]
    It would be most economical to rebuild yours - yourself, rebuilders are going to want a bunch of money.

    [ QUOTE ]

    3) Maybe I can switch out components between my case and the other one to make his compatiable with my trans?

    [/ QUOTE ]

    You could switch the input shafts between them when you rebuild it, but then yours would be out of service anyways.


    [/ QUOTE ]
     
  3. SkyScraper

    SkyScraper Registered Member

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    [ QUOTE ]
    TH350 output spline is 27
    TH400 output spline is 32


    [/ QUOTE ]

    That sucks, but was expecting it. He does have a 400 turbo tranny sitting next to it. I could do the same with the tranny and replace both the tranny and the transfer case. But that seems like more work than I want to do, along with the cash I would have to shell out.

    [ QUOTE ]
    It would be most economical to rebuild yours - yourself, rebuilders are going to want a bunch of money.

    [/ QUOTE ]

    For 1) I have no idea what I'm doing
    2) I can't get it out myself - I don't have the tools to get it out.
    3) I couldn't get it done in a reasonable time frame. It would be snowing by the time I got it done. /forums/images/graemlins/grin.gif

    [ QUOTE ]
    You could switch the input shafts between them when you rebuild it, but then yours would be out of service anyways.


    [/ QUOTE ]

    What do you mean out of service? I don't folow you /forums/images/graemlins/confused.gif

    Thanks for your help and insight! /forums/images/graemlins/thumb.gif
     
  4. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    I believe that the th400 203 is a much rarer case than the th350 203. You should be able to find a cheap 203 to fit on your th350, probably even one tha works. The th400 203 would be worth some money to someone wanting to make a doubler and has th400 tranny...Just a thought...
     
  5. sapper

    sapper 1/2 ton status GMOTM Winner

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    [ QUOTE ]
    The th400 203 would be worth some money to someone wanting to make a doubler and has th400 tranny...

    [/ QUOTE ]

    Thats what i was thinking, if i had a friend with that tranny, t case it would find its way into my rig /forums/images/graemlins/thinking.gif /forums/images/graemlins/thinking.gif
     

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