Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Swapping Advice for 700R4 or 4L80E

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Fletch79, May 24, 2003.

  1. Fletch79

    Fletch79 Registered Member

    Joined:
    May 14, 2003
    Posts:
    63
    Likes Received:
    0
    Location:
    Southern Wisconsin
    '79 K5, 400SB, TH350, NP203, GM 10-Bolt front and GM 12-Bolt rear.

    I want the overdrive gear.

    What's involved in the swap?
    Do I have to change T-cases? Driveshafts?
    Need Adaptors?

    How tough is it to get the E-trans to run right in an old truck?

    Thanks Folks,
    Fletch.
     
  2. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    You will need trans, a 208, 205, or 241 case and whatever it takes to mate them together, driveshafts, and a crossmember. You'll want to wire the tcc lockup too with either a kit or make your own from schematics that can be found online.

    I have never seen a 700 bolted to a 203 although I'm sure it could be done with the correct adapter as a TH 350 and 700R4 share the same spline count output.

    I can't see trying to keep the NP 203 though, it's heavy and still chain driven and the low range sucks compared to the lightweight aluminum cases. Unfortnately though, the 1-208 and 241 are both slip yoke rear output. The 241 can have a SYE installed though. 241s are kinda tough to find, but on here you can find anything.

    Ask any more specific questions after doing a search and we'll help you out.
     
  3. arq

    arq 1/2 ton status

    Joined:
    Jan 17, 2001
    Posts:
    2,017
    Likes Received:
    0
    Location:
    Imperial Valley/Maricopa
    advanced adapters makes an output shaft for the 700r to mate it witha np205, if it works witha 205 it will work witha 203.

    ARQ.
     
  4. 73K5Kid

    73K5Kid 1/2 ton status

    Joined:
    Sep 24, 2002
    Posts:
    583
    Likes Received:
    0
    Location:
    chandler az
    The advance adapter output shaft will also work with the 203. You can use the shaft for both. I am running a 203. If you have any questions with the swap pm me. I just did the swap with a little help /forums/images/graemlins/grin.gif
     

Share This Page