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What would be the optimum trans for a 454?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by spincast375, Apr 23, 2005.

  1. spincast375

    spincast375 1/2 ton status

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    My 454 is matched to a TH350. The trans always seems to leak no matter what I do (have replaced the pan gasket several times). I suspect maybe a hair line crack in the case because it is so undersized for the engine. Any suggestions?

    What would be the optimum trans for a 454?
     
  2. sweetk30

    sweetk30 professional hooker Premium Member

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    th350 o.k. if built correctly and k case with the brace rods. but th400 was factory behind them. my friend runs th350 in his 454 bigblocks trucks. no problems.
     
  3. ratzila

    ratzila 1/2 ton status

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    I have used both the sm465 & th400 bolted to the 454. Either one is great.
     
  4. J.R.

    J.R. Guest

    ive used th350 behind 600 plus hp big blocks with no problems. a well, and proper built 350 will do the job but like you said it may have a crack that is causing the leaks. try adding some dye to the fluid and use a black light to find where the leak is.
     
  5. sweetk30

    sweetk30 professional hooker Premium Member

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    the dye works . any good auto shop like napa will have it. its about 5 bucks or less. and just need a light and glasses just like the a/c system dye uses.
     
  6. grimjaw

    grimjaw 1/2 ton status

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    I love my 4L80e.
     
  7. 85HeartBurb

    85HeartBurb 1/2 ton status

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    I cracked the bell housing on my th350 so i went with a th400 so far so good........ :D
     
  8. 75-K5

    75-K5 3/4 ton status

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    You can never go wrong with a sm465 behind a BBC.
     
  9. chevy_addict

    chevy_addict 1/2 ton status

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    For those of you running 454s and SM465s, do (did) you have any issues with the gear splits in the SM465, particularly when towing uphilll?

    Dave
     
  10. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    my thoughs to the "T"
    a 4l80e is the ONLY auto trans in a RWD vehicle i have not blown up. i had my th350 built several times by "one of the best in the area" and i could not keep it alive with a SM350. i had a stock 4l80e behind a 96 vortec 454 with a cam, computer, intake, full exhause and head work. i beat the everlivinghell out of that truck and NEVER once had a problem with the tranny.

    oh, other two on my vote since im a manual guy is an SM465/420 OR and NV5600.
    Grant
     
  11. sweetk30

    sweetk30 professional hooker Premium Member

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    ya if time and money alow 4l80-e all the way.
     

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