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converting 2wd Th400 to 4wd Th400

Discussion in 'The Garage' started by Disciples Performance, Mar 18, 2007.

  1. Disciples Performance

    Disciples Performance 1/2 ton status

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    hey guys so i blew the front seal on my 700r4

    so now i have a short tail shaft th400 2wd sittin in my garage doing nothing so i was thinking is it possible to convert it to 4wd without alot of hassle???

    anyone done this before? do i just need the kit from advanced adapters??

    Thanks

    Nick:D
     
  2. SkysTheLimit

    SkysTheLimit 1/2 ton status

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    Chances are you'll need to swap the output shaft which as I understand requires a complete teardown to do. I looked at swapping in a 400 I have that is built 9 ways to Sunday and that is what I would have had to do. My trans guy locally was going to do it for about 200 bucks IIRC and then i'd need the adapter for th400 to np208.
     
  3. Disciples Performance

    Disciples Performance 1/2 ton status

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    hmmm interesting ive also heard certain yr th400 short tail shafts dont need to be shortened also heard some needed as much as 5/8" taken off of the output shaft! yikes im not keeping my 208 haha goin to a 10 spline fixed yoke 205
     
  4. fatbob

    fatbob 1/2 ton status

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    You'll need a new transfercase also.:doah:
     
  5. SkysTheLimit

    SkysTheLimit 1/2 ton status

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    There's something like 10 different shafts used on the 400's. You may get lucky, I was not. Pic was courtesy of another member when I was going through this. Reposting for anyone who missed it.

    TH400 shafts.jpg
     
  6. Disciples Performance

    Disciples Performance 1/2 ton status

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    i cant see the pic cause im not a full member yet :( is there any other way you could post it for me or e-mail it to me! ddr_bot@hotmail.com
     
  7. MEK5

    MEK5 1/2 ton status

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    Heres a modified version of that chart

    th400shafts%2520002.jpg
     
  8. blazin_blazer

    blazin_blazer 1/2 ton status

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    most th400 have a 32 spline output shaft and an original np205 for a th400 has a 32 spline female input shaft, so you will need a 32 to 10 spline coupler plus the th400 to np205 adapter.

    i was looking into doing the same thing, except i was using a 27 spline np205 from behind a th350. after much thought about strength and cost comparisons, i decided to buy the right th400 output shaft and the female input shaft for the np205 and have my np205 case machined, for the new shaft seal(i believe that is why you have to have the case machined. any1 have the specs and reason a th350 np205 has to be machined to build it like gm did for a th400?) then use the th400/np205 adapter, so that it is built just like the original 1 ton th400/np205. anything incorrect someone please set the record straight!
     
  9. Disciples Performance

    Disciples Performance 1/2 ton status

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    guys id love too see the pics if you could please e-mail em to me that would be awesome!!!! ddr_bot@hotmail.com
    ya i know i can get a 32 spline to 10spline adapter from advanced adapt. but im just wondering if i get all that stuff should the t-case just bolt right onto it?????
     
  10. SkysTheLimit

    SkysTheLimit 1/2 ton status

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    I emailed you earlier in the day.
     
  11. thatK30guy

    thatK30guy 1 ton status Premium Member

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    The 2wd version th400 with the 9 1/4" long shaft can also be used in front of a 205.
     
  12. Disciples Performance

    Disciples Performance 1/2 ton status

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    is if it has that tail shaft length it should just bolt on???
     
  13. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Yeah, my bro-in-law did it once.

    He had a 205 out of an '84 K30 and searched high and low for a 400 to bolt to it.

    Turned out his dad had a 400 out of some car or truck that had the proper length so he used a 2wd tranny. Most people use 2wd housings anyways, so it didnt affect anything.
     

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