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TH400 Tranny swap

Discussion in 'The Garage' started by donoh24, Oct 29, 2003.

  1. donoh24

    donoh24 Newbie

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    Can I swap a Turbo 350 for a Turbo 400. I have a TH350 with a NP203 T-Case and want to swap in a TH400. The TH400 came out of my '87 2wd D.O.T. truck that I am now parting out. Will the T-Case bolt up if I slip off the tail shaft of
    the TH400 and slide the T-case on? Is there a length difference?

    I also have a rearend for sale if anyone is interested. It came out of the same 2wd D.O.T. truck. The good part about the rearend is that it is a limited slip diff. The bad part is the 3.08 gears inside it.

    Thanks for the help.
     
  2. dhdescender

    dhdescender 1/2 ton status

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    Location:
    Qualicum Beach, British Columbia, Canada - Eh.
    1) The TH400 has a differnt diameter and spline count rear tailshaft, not to mention tailhousing. Essentially with all the variables involved, your better off to find a 4x4 TH400. The TH400 you have currently, you would need to find a new input gear for the 203, a TH400 to 203 adaptor, and a new tailshaft for the TH400

    2) There is a place for for sale items. If you cannot post b/c your not a member....well we all know how to fix that! /forums/images/graemlins/thumb.gif

    Hope that gives you some insight.
     
  3. R72K5

    R72K5 Banned

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    Location:
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    you would have to have a shop completely disassemble the 2wd tranyn and reassemble with 4x4 output in order to use it with a transfer case, IE 4x4

    you need to find a 4x4 th400 and then youll have to find a th400 203 case and adapter too,

    $$$$$$$

    good luck
     
  4. blasterD

    blasterD 1/2 ton status

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    I've heard that a 2 wheel drive th400 and a 4wheel drive th400 are the same after you take the tail housing off. I may be wrong though. You will have to get a np203 that has a 32 spline input (original th400). I'm sure someone else on this board knows more info on this subject.
     
  5. dhdescender

    dhdescender 1/2 ton status

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    Location:
    Qualicum Beach, British Columbia, Canada - Eh.
    There are 3 4x4 TH400 trannies.

    One is for a NP203
    One is for a NP205
    One is for a NP208.

    So, I would be interesting in knowing is one is the same as a 2wd Tranny, b/c as far as I knew they were all different.
     
  6. 77fixer

    77fixer 1/2 ton status

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    The 2wd TH400 does fit with the pre-85 32 spline 205. Just need the adapter and plug the hole in the 400 case where speedo drive went. As far as that goes get a SM465 version 205 and convert it to the 32 spline.
     

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