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Will a 78 K5 tranny / t-case work in an 84?

Discussion in 'The Garage' started by ellero, Jul 31, 2006.

  1. ellero

    ellero Registered Member

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    I just bought a transmission and transfer case from a 1978 K5 to put into my 1984. When I look at the transfer cases the one from the 78 is much larger. I have not yet removed the transmsission. Should these interchange? I also notice that the 78 T-case is NOT a slip yolk. Any clue what kind ot T-case it is? Thanks

    John
     
  2. purplehavoc

    purplehavoc Registered Member

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    Is it a manual or auto tranny?
    Assuming it is an auto the 78 should be a 350 or a 400.
    The t-case should be either a np205 or np203.203 is the full-time chain drive.
    Your 84 should have the np208,aluminum with a slip yoke,and probably a 700r4 infront of that.
    Splines are different between the 78,84.
    The 78 combo will bolt in,need to drill new crossmember holes and maybe new crossmemeber.may have to rework driveshafts as well.
     
  3. big dan

    big dan 1/2 ton status Premium Member

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    yes it should work as mentioned. I just installed a 79 tranny and transfer case in my 84. I took out a 350/208 and installed an sm465/205. had to install a clutch cause it was a manual swap and had to redrill crossmember bolts but other than that it was a direct bolt in.
     
  4. ellero

    ellero Registered Member

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    its not full time 4x4, but it has 4 settings + neutral. 2 of the transfer case settings only activate the rear end, 1 activates both front and rear low, 1 activates front and low high and one is neutral. This seems odd. Was there an extra setting in 78?
     
  5. big dan

    big dan 1/2 ton status Premium Member

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    sounds to me like a 203 that has a part time kit in it.
     
  6. chevyryan

    chevyryan Registered Member

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    the only thing i can tell u is that the 84 im guessin has a 700r4 trans which is much better than a 350 or 400 and the 79 t-case is probably a chain driven one. they bolt up but u may need to do a liitle work on the crossmember is what im guessin
     
  7. NoReGrEtS

    NoReGrEtS 1/2 ton status

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    :confused: :confused: :confused: I think you have it backwards,If it were a Freeway thing mybe
     
  8. ellero

    ellero Registered Member

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    What is a part time kit? I always thought it was 2H, 4H, and 4L.
     
  9. chevyin

    chevyin 1/2 ton status

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    :eek1: :eek1: :eek1: much better?:haha: :haha:
     
  10. purplehavoc

    purplehavoc Registered Member

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    Part time kit takes your fulltime 203 and converts it to part time,and allows you to install locking hubs.
    The 203 should of had lo-loc,lo,nut,high,high-loc.
    Would still bolt in.
    Unless you have a 700r4 built up,stick with a 350 or 400.
     

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