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Manual to auto transmision swap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by taz8000, Mar 19, 2002.

  1. taz8000

    taz8000 Guest

    I own a 81 pick-up truck with a manual transmision and would like to change this over to a TH700R auto trannie, is this possible. I have a trannie and torque convertor out of a 85 6.2 Diesel Suburban.
    Can I use the same drive shaft (is the manual trannie as long as the auto)
     
  2. DesertDueler

    DesertDueler 1/2 ton status

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    You will need driveshafts from a 81-91 truck, and you would have to change governors in the tranny unless your truck is a diesel.
     
  3. lax037

    lax037 Registered Member

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    Also keep in mind the spline count out of your current tranny and the one you plan to install. you might need to change your t-case along with your tranny.

    Tom
     
  4. fortcollinsram

    fortcollinsram 1/2 ton status

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    What manual do you have in your truck and what t-case do you have?I am guessing a 465/203 (???) combo...It is very possible...I am in the process of going the other way (auto->manual)...Here are some things to keep in mind...

    1. If you have the 700r4 and the TC, you MAY need a new t-case or and adapter to make your current t-case work with your auto tranny...I would try to find a 208 t-case w/ 700 adapter to simplify things
    2. You will need to get a bracket to hook up the TV cable to your throtle linkage at the carb (<a target="_blank" href=http://www.tvmadeez.com>Try TV MADE EASY</a>).
    3. You will need the auto shifter assembly
    4. A new cross-member
    5. New drive shafts (fornt and rear) probably just yank 'em from a similar year truck with an auto
    6. A new flexplate and possibly a new starter for your engine...


    I think that is it...If I thinik of anyhting else to consider, I will let you know...


    Chris
     
  5. taz8000

    taz8000 Guest

    I forgot to mention it is a 4x2 truck.
    BTW, what is a governor
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    81 would have a 32 spline SM 465 mated to a NP208. The 700R-4 is a 27 spline output so it won't bolt up to the T-case.

    The best way to accomplish the swap would be to find a tranny/T-case combo and swap the works...

    Personally I'd keep the SM 465 though, it's about 10 times stronger and more reliable than the 700R-4.

    Rene
     
  7. fortcollinsram

    fortcollinsram 1/2 ton status

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    If it's a 2wd truck...It easy...Just get a driveshaft from that year truck w/ and auto, get the shifter assembly and the TV cable bracket, flex plate and have at it...

    Chris
     

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