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Non-mechanic asking stupid transmission question.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Eagle, Jun 18, 2001.

  1. Eagle

    Eagle Registered Member

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    I have read a lot of articles about hard core off roaders swapping their TH400 or TH350 transmissions for the 700R4. They do this because the 700R4 has a lower (or higher I forget which) first gear. According to them they would rather sacrifice the strength of the TH400 / TH350 transmission for the gearing. Insert stupid question here. Couldn’t you just rebuild a TH400 trans with lower gears? Is this something that can be done or would it cost tons of money?

    There is a VERY fine line between hobby and mental illness
     
  2. 90K5

    90K5 1/2 ton status

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    The 700R4 has a lower first gear, its 3.06:1, the TH350 has 2.52, TH400 has 2.48...700R4 is also overdrive..

    90K5

    See my truck at <A target="_blank" HREF=http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502>http://albums.photopoint.com/j/Albumindex?u=1329584&a=9886502</A>
     
  3. Jason73K5

    Jason73K5 1/2 ton status

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    I might be wrong, but I think there is a lower first gearset available for the TH-400.
     
  4. Blue85

    Blue85 Troll Premium Member

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    There is a lower gearset available for the 700, or actually it is a broader gearset. First and second are lower, but 3rd and 4th are still 1.0 and .69.

    One reason that you would swap instead of rebuilding is that the swap would be cheaper than buying the custom gearset (if it is available) and rebuilding the 350/400. You could also regear the axles, but that would be just lower instead of broader. A higher stall torque converter would also help in the same area.

    <font color=green>If a K-5 is "Built not Bought", why does this stuff cost me so much money? [​IMG] </font color=green>
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    A 700R4 is a great tranny. It's strong enough for small block power in stock form and anything in modified form. It has a real stump-puller 1st gear. In fact, I might only have a 305, but I'll race and stomp any of you guys on here that have small blocks and TH 350s or TH 400s. The overdrive helps a lot too.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  6. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    i never knew you raced 4x4's.....
    and if you did it would be in the mud... so a lower gear is not really needed.... am i wrong?

    1974 Chevy Blazer Cheyanne. lots of plans for it....
    but it is on 33's now, with saggy old springs. i am in so cali if ya got any parts for me.
     
  7. Bigd

    Bigd 1/2 ton status

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    A-1 tranny sells a lower gear set for the 400 and 350.I have a 3.00 to1 low gear set for my t400.If they where racing and really torturing there tranny i dought they would use a 700r4.Its not even recommended too tow in overdrive so i don't think the over drive helps there.just my 2 cents
     
  8. 84_Chevy_K10

    84_Chevy_K10 Banned

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    My point was just that a 700R4 really makes a vehicle perform better. No intentions on racing my 4x4.

    Lower gear not needed in mud? Are you nuts?

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     

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