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4L80E/NP205 Combo

Discussion in 'The Garage' started by ccj8008, Jan 24, 2006.

  1. ccj8008

    ccj8008 1/2 ton status

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    I have located the elusive 4L80E/NP205 combo available only in 1991 V3500 crew cab duallies (7.4L). The seller wants high dollar for the transmission. My question is: Will the 4L80E from a 1991 3/4 ton Suburban (5.7L) bolt up to this NP205 or does it have a different output shaft? I ask because the Suburban transmissions are more common than the duallies and I can pick these up cheaper. Thanks.
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    all the 4L80E's have a 32 spline output so any 205 with the same input will work all you need in the correct adaptor but the bruds trannys will work
     
    Last edited: Jan 24, 2006
  3. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    Yup you need to get the adapter with the tranny.
    What is the trans. for your suburban 3/4 ton NP205? If not a 32 spline th400 version, that is what you will need to convert the transfer case to.
     
  4. sweetk30

    sweetk30 professional hooker Premium Member

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    i used a old fig 8 32 spline 205 with my 4l80-e that was 2x4 fixed yoke and made a spacer to take up the diffrence. and a few other little things.

    205 spacer.jpg
     
  5. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    The NP241 Adapter happens to be the perfect size to connect the two:

    [​IMG]

    You can just make it out in this pic:

    454 / 4L80E / NP241 Adapter / 203 / Doubler / NP205
     
  6. steve_kibbe

    steve_kibbe 1/2 ton status

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    Thats nice:bow:
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Not sure if that statement is correct.
    There are two different output shaft lengths on 4L80's (2wd vs 4wd).
    There are also two different 32 spline input lengths on 205's (early model short and late style long) as well as two different mounting bolt arrangements (early figure 8 and late circular 6).

    Not to hi-jack as this may help, but I have a long 32 spline input np205 with round pattern adapter along with a round pattern TH400/NP205 adapter. My question is will this combo work to bolt to a 4wd 4L80 or do I need the short NP205 input gear?

    I also know the adapter has to be machined to match the lip on the 4L80, but wanted to know if their are any CK5 members/vendors that will do this machining?

    Thanks.
     
  8. ccj8008

    ccj8008 1/2 ton status

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    Thanks for all the input guys. I am assuming the 1991 3/4 ton Suburban had an NP241 t-case behind it and that is already sold. So from what I have heard, I am going to buy the 1991 Suburban 4L80E and then the NP205 with adapter from the 1991 Crewcab dually.

    I have got an 89 454 from a 1 ton dually swapped into my 77 Blazer. I have the TBI and computer from the same truck. I plan on grabbing the wiring harness, steering column, speedo etc from the dually to make the swap in place of my sm 465. I think the computers are the same.

    If JB conversions has finished their 3:1 parts for the NP205, I think I will send the case over there for the upgrade.
     
  9. muddybuddy

    muddybuddy 3/4 ton status

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    thats probably one of the best combo's you can make! :bow:
     

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