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best tranny

Discussion in 'The Garage' started by geeman, Mar 13, 2007.

  1. geeman

    geeman Registered Member

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    i have a 1974 chevy pick up on 38's. i have a 350 v8 it came with a 700 tranny and a np241 transfer. my question is would a th350 tranny work better? any info would be helpfull
     
  2. Jason4x4

    Jason4x4 1/2 ton status

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    If you are staying with an automatic, stay with the 700r4, lower first gear and overdrive.
     
  3. geeman

    geeman Registered Member

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    yeah im staying with automatic
     
  4. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    yeah, keep the 700r4. If you are worried about it, you can get em built up a bit. Th350s are a bit stronger, but not enough to warrant changing em out, in my opinion
     
  5. 454k30

    454k30 1/2 ton status GMOTM Winner

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    keep what you have, you will never regret that overdrive.
     
  6. geeman

    geeman Registered Member

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    oh ok. i have 38's what gear ratio would be good?
     
  7. 454k30

    454k30 1/2 ton status GMOTM Winner

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    this is an eternal question that has been asked a lot! There really is no right or wrong answer, more of a preference really. Since my truck sees a lot of highway miles going to and from trails I kept the stock 4.10 gearing. With 37in tires this puts me short of 3000rpm at 60mph. I do not have overdrive and the engine seems pretty happy cruising at this rpm. I can tell you that when the day comes that this truck becomes a truggy that 5.13's or higher will fill both diffs because the crawl ratio will become much more important than the MPG.
     
  8. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    General idea is to get your rpms around 2000 - 2400 at 60 mph. Unfortunately, without overdrive that can make your truck a real slug off the line... You'd be able to get away with 4.56, but I'd reccomend the step up to 4.88 or 5.13
     
  9. muddybuddy

    muddybuddy 3/4 ton status

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    ive got a deep overdrive, run 5.13s. i ran 5.13s with 39.5's and i loved it with 700r4
     
  10. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    if you plan on driving on the street: keep the th700.

    when your rig becomes offroad-only: th400.

    OD is cool to have on the highway, but really isn't worth jack offroad... and the th400 is much more durable.

    j
     
  11. resurrected_jimmy

    resurrected_jimmy 1/2 ton status

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    4.88's if your on 1/2 ton axles
     
  12. geeman

    geeman Registered Member

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    so if i change my gear ratio in one differential i have to change it on the other one? im i right or wrong?
     
  13. resurrected_jimmy

    resurrected_jimmy 1/2 ton status

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    have to do both diffs. Not changing gears in the front = broken parts
     

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