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TH400 Beef

Discussion in 'The Garage' started by txfireman110, Feb 2, 2004.

  1. txfireman110

    txfireman110 1/2 ton status

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    What HP will a TH400 handle?
    The rest of the set up will be: 454 mildly built, NP205, D60, 14ff. Will have 38's to start, but MIGHT go to 44's in the DISTANT future. BTW, this is going in my K5 /forums/images/graemlins/woot.gif
     
  2. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    A th400 built to the gilles can handle 1000+ HP in 1/4 mile cars.
     
  3. bam bam k5

    bam bam k5 1/2 ton status

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    I have friend with a 83 K10 with a 427/400/205. the motor has about 400hp and has not had any problems with this set up for about 2 years.
     
  4. txfireman110

    txfireman110 1/2 ton status

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    So what mods do I need to make? /forums/images/graemlins/thinking.gif
    Thanks! /forums/images/graemlins/bow.gif
     
  5. k5blazerus

    k5blazerus 1/2 ton status

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    The th400 is the better of the Hd transmissions. I have one in my truck. It has corbon kevlar clutch packs. strait cut planatary gears and lower gear ratio on first gear. shift kit and a modified valve body. Basically it is what the tranny guy calls a th475. I have had no problems with this tranny what so ever and it gets used and abused plenty. I have a temp guage on it and I hardly see it go over 125 Degrees
     
  6. thor

    thor 1/2 ton status

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    They will take a lot of power, weak point is usually the stock intermediate sprag that can break hitting second under power. That and good clutches and you will be set. Very seldom do they actually break hard parts even with insane power and traction.

    K5Blazerous has the ultimate, because of the lower first gear... I'm jealous, wanna 465? Where did that originally come from a school bus or ryder type truck?
     
  7. tarussell

    tarussell 1/2 ton status

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    You may want to PM NEVERENUF ( John ) and ask him about the upgrades on every TH400/475 that has been in his truck .
    He use to run a NASTY Roller BBC and it killed a few J.W. prepped 400's after continued skinny pedal abuse .
    TH400's are damn sure strong but with enough torque and traction anything will break .
    Tom
     
  8. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    A lot of guys change the input shaft to a lot stronger one.....
     
  9. Muley

    Muley 1/2 ton status

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    not to high jack, but do you have any pics of your tranny temp gauge set up? Like where you mounted it up in the cab, as well as the set up at the pan?
     
  10. boz42

    boz42 1/2 ton status GMOTM Winner

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    i put a hardened input sprag assembly into mine also went manuel reverse valve body so i could have 1st & reverse closer together & to have complete control on when she shifts. kinda a pain on the street, but the K5 don't see the asphalt often. my tranny man modified the frt pump to have more line pressure for better clutch life.

    most important on any tranny is run the best cooler u can afford. more expensive coolers are often much better than your cheapo A-Zone coolers also.
     
  11. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    A lot of guys change the input shaft to a lot stronger one.....

    [/ QUOTE ] Whats done to yours mud? You gotta be running something beefy or it would be done in one outing with your motor... /forums/images/graemlins/waytogo.gif
     
  12. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    hardened input shaft,34 element sprag, kevlar plates,Heavy duty bands, manual valve body,Going to a Ultra-bell" bellhousing soon /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  13. jeffro

    jeffro 1/2 ton status

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    I second the th475. These are used to propel GMC motorhomes. I read an article in peterson's years ago and it looks pretty good to me.
     
  14. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    [ QUOTE ]
    I second the th475. These are used to propel GMC motorhomes. I read an article in peterson's years ago and it looks pretty good to me.

    [/ QUOTE ]Rare, Good luck in finding one /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     

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