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np 205 t case questions

Discussion in 'The Garage' started by 85burbanator, Oct 29, 2005.

  1. 85burbanator

    85burbanator 1/2 ton status

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    im in the process of wapping out a 700r4/np 208 combo for a th400/np 205 combo. the mounting adapter looks like this http://cgi.ebay.com/ebaymotors/Adap...ryZ33733QQssPageNameZWDVWQQrdZ1QQcmdZViewItem and it puts the mount way down there. it had that little coupler in there as well. it worked fine like that but i was wondering if the mounting adapter was dirfferent for a th400 trans ive looked and cant seem to find anything. either im dumb or my comuter is because all my searches dont turn up much.
     
    Last edited: Oct 29, 2005
  2. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Yes, the adaptor is different. On the 400 side, its shaped like a stop sign with 6 bolt holes. Not quite like a stop sign but does have 6 sides to it. Look on the back of any 400 tranny and that will give you an idea of the shape of the adaptor.
     
  3. muddybuddy

    muddybuddy 3/4 ton status

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    there are also differnt spline counts so make sure urs will match up. dont think spline count effects adaptor...but i could be wrong
     
  4. 85burbanator

    85burbanator 1/2 ton status

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    were can one find this adapter? ive searched the internet and called a few salvage yards but turned up nothing. there is one place im going to check out because he has no phone but he does nothing but old chevy trucks.
     
  5. thatK30guy

    thatK30guy 1 ton status Premium Member

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    I believe you can get the adaptor from Randy's Ring & Pinion. Its a new aftermarket type adaptor thats stronger than the stock piece and I think a stronger material, too.

    Keep in mind, there are 2 different 400/205 adaptors. You need to get the 32 spline 205 t-case before you pick an adaptor for it, that is if it doesn't come with one.

    If you're interested, I have a complete 205 with the adaptor to fit a 400 tranny to sell you. Its the newer '85-'91 case with the round 6 bolt pattern adaptor and a shifter, too. UPS will ship the case as I've done it before. The adaptor and shifter would be in a second box. Shipping ran in the $100-range.
    Something to think about so you can just get everything in one deal and not have to scrounge around for parts. :thinking:
     
  6. 85burbanator

    85burbanator 1/2 ton status

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    the trans has a 10 spline output shaft and the t case has a 10 spline shaft and they used the coupler to attach. to use a 32 spilne would mean that id need a new output shaft on the trans correct?
     
  7. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Well, this is where it gets a little more into swappability concerns.

    There are no 10 spline shafts to swap into a 400.

    10 spline shafts are considered the "weakest" of the 3 different spline counts.

    10 spline fits the 465 manual tranny.

    27 spline fits the 350 and 700R4 and 4L60E (I believe) trannys.

    32 spline fits the 400 and 4L80E trannys.

    To make a long explaination short, you simply need to find either one of two things: 1) 32 spline input shaft for the current 10 spline 205, or, 2) find a complete 32 spline 205 t-case.

    You can't do anything to the 400 as far as spline count goes. You can change the shafts out for different lengths, but thats it.
     
  8. 85burbanator

    85burbanator 1/2 ton status

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    but the 10 spline on the trans is ok or is it a bastard child so to speak? im new to trans and tranfercase swaps so i appologize for any retarded questions.
     
  9. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Are you planning to use the trans now? I thought you wanted to use a 400.

    If you still want to use the 400, get rid of that 465 and forget about it. Its the least of the swapping worries for a 400 and 205. Just ignore it.

    Concentrate more on the 205 you have on hand. If you don't have your 400 tranny yet, I suggest you find one before you do anything else to the 205.

    Once you have found your 400, a rebuilder or a runner, then we can see what you have as far as the length of the rear output shaft goes. Depending on the lenght of that shaft will determine which 32 spline 205 t-case you will need.

    But as for the 10 spline stuff, forget them and if it helps any, try to sell the combo off to recover some money you will need to buy the 400 and/or 205 instead.

    If you're interested AGAIN, I have a matching 400/205 combo here at home with EVERYTHING you will need for a swap. No looking for parts or anything. Everything is there. Just need to rebuild the 400 and install everything after that.

    There, don't that make it sound easier and more interesting to you? :waytogo:
     
  10. 85burbanator

    85burbanator 1/2 ton status

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    the trans is a 400. has the vacuum modulater and everything. im starting to get alittle confused here now. you say that there are no 10 spline 400 trannies but i have one. im starting to think maybe he some how got a 10 spline shaft into the 400 trans so he could run this combo. it cam out of a k5 that i purchased last year to rebuild but never go around to it. how much are you asking for your combo? you can email me at bigbir5829@aol.com
     
  11. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    i think advanced adapters makes an output shaft for different spline counts on the end, gm never made a 10 spline th400 shaft, but AA did.

    ive seen a few adapters from th400 to np205 on ebay before, just keep and eye out.
     
  12. 85burbanator

    85burbanator 1/2 ton status

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    hmmm. maybe thats what the po did to get the combo to work. so realisticly all i have to find is a 35 spline output shaft for the trans and an 35 spline input shaft for the tcase. anyone know were i can find these items?
     
  13. boz42

    boz42 1/2 ton status GMOTM Winner

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    to mate a 400/205 u need a 400/205 adapter. your 400 needs a 32 spline output. & your 205 needs to have a female 32 spline input.

    look HERE

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    [​IMG]
     

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