Overdrive Options

Discussion in '1973-1987' started by mrgbody, Oct 29, 2002.

  1. mrgbody

    mrgbody Member

    Joined:
    Jul 28, 2002
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    Location:
    Newtown
    Hey Everyone,

    Here comes the oddball question of the week:

    I recently purchased a partially finished 1978 GMC Shortbed 4X4 project. The engine runs great but the trans is toast(or so I was told). The cab is still off the frame and I want to change the trans before putting the cab back on. So here's the question...can I substitute a 200R4 trans for the current Turbo 350? I've been playing with GM G-Body cars for the last 10 years or so, and it's a common swap. As far as I've ever known, the 200R4 is a direct replacement for the Turbo 350, and you gain OD. Has anyone done this? Am I out of my tree? I really want the OD, and don't really care about off-road prowess. I plan on driving the wheels off this thing (on the street).

    Thanks for any advice you've got,
     
  2. 74X4Burb

    74X4Burb Member

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    Location:
    Fort Shaw U.S.A
    [updated:LAST EDITED ON Nov-21-02 AT 02:14 PM (CST)] I dont know anything about a 200r4 but a 700r4 is about the same size as the th350.Hope this helps some. Good luck. Karl


    ________
    Herbal vaporizer
     
    Last edited: Mar 16, 2011
  3. 87_Chevy_4x4

    87_Chevy_4x4 Member

    Joined:
    Nov 25, 2002
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    27
    Location:
    Newtown USA
    Yeah, it should bolt right up without any problems. I got one in my truck, and it works just fine.
     
  4. mrgbody

    mrgbody Member

    Joined:
    Jul 28, 2002
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    Location:
    Newtown
    OK, 700R4 it is. I just found one in an '85 Blazer...diesel. Make my day and tell me that stupid 6.2 has the same bellhousing as a SBC...PLEASE!!!!
     
  5. 57heaven

    57heaven Member

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    Aug 18, 2002
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    Location:
    Honolulu America the Beautiful
    :) howziit Roy!

    interesting coincidence!

    i have a TH-350 in THE PINK LADY. since this isn't the most reliable trans, to use behind a big-block chevy, and because the U-joint is clunking, i was thinking about swapping to either a built 200R4/700R4, or TH-400 trans.

    i'd REALLY like an overdrive trans, for gas mileage purposes. HOWEVER, since i don't travel far on freeways, the cost difference over the TH-400 trans might not be worth it.

    still up in the air...thinking about it. }>
     
  6. jukele

    jukele Member

    Joined:
    Jan 1, 2000
    Messages:
    5
    get the 700r4, but be sure it is a post '84 model. the earlier trans had reliability problems which were cured in the later years.also, be sure to get one from a 4x4 model. I built a 700r4 out of a '86 suburban and put it in my '80 one ton 4x4 with a mild big block. it cruses down the highway at 70 turning 2000 rpm. The truck also gets 114-17 mpg on the highway with the ac on. perhaps the best mod i've made yet.
     

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