Found a Th400 in a Suburban.Will it work...

Discussion in 'Transmission & Driveline Topics' started by Powerglide350, Aug 25, 2004.

  1. Powerglide350

    Powerglide350 Veteran Member Lifetime Gold Member

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    ..In my 81 Z? The Suburban is an 84 2WD. What would I need to make this work?
     
  2. rscamaro73

    rscamaro73 Administrator Staff Member

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    Lemme know the length and I'll measure it against the one I have.

    You'd need the tranny & converter & yoke. [​IMG]

    D/S is different....flexplate won't work unless you're is the same type of motor and matches in balance....
     
  3. Powerglide350

    Powerglide350 Veteran Member Lifetime Gold Member

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    I'm getting the whole truck. I'm using the motor too [​IMG]
     
  4. Eric

    Eric Veteran Member Lifetime Gold Member

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    All TH-400s are the same physical size. They are longer than a TH-350 and 2nd Gen manual transmissions, so re-locating the crossmember will be needed, as well as shortening the driveshaft and using the front yoke from either the TH-400 or a BW ST-10 transmission.

    The converter is not a big deal- the TH-350 and TH-400 can use the same converters- so you could use any aftermarket unit (not the one from an 81Z if it was auto- it would be a lockup converter- which the 400 isn't equipped to handle).

    If the engine in the suburban was a Chevy unit (it would be from factory- so unless someone swapped engines for a BOP of some sort) the housing mounts will be the same as any Chevy smallblock or bigblock. Seeing as how you're going to use the motor anyways- just verify it's a Chevy setup or you may also be re-arranging your engine mounts.

    Edit: You'll also need to hook up a switch for the 400's kickdown- look at the topics in this area and there was one about a week ago talking about doing this using the 80-81 gas pedal switch for the air induction hood and a relay.

    [This message has been edited by Eric (edited August 26, 2004).]
     
  5. Powerglide350

    Powerglide350 Veteran Member Lifetime Gold Member

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    Thanks for the advice. Is the kickdown mandatory or can I just do the downshift routine?
     
  6. rscamaro73

    rscamaro73 Administrator Staff Member

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    Prolly be easier overall to hook up the kickdown....

    What motor was in the burb ???

    <BBC??> [​IMG]
     
  7. tom3

    tom3 Veteran Member

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    Not up on automatics but I think the kickdown is more than that on these. If this is the TVS cable it controls pressure in the tranny, softens the shift at low rpms and throttle position to reduce slamming when going into gear and such. If left unhooked the trans might slip some when shifting at speed.
     
  8. Eric

    Eric Veteran Member Lifetime Gold Member

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    TH-400s do not have a TV cable setup- only a solenoid to control kickdown...
     
  9. Powerglide350

    Powerglide350 Veteran Member Lifetime Gold Member

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    It's got a 350 Crate Motor. Thanks again.
     
  10. wayner

    wayner Veteran Member

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    THM400 trannys can come with either a 4",9" or 12" tailshaft. Most used in cars are the 4".
    Makesure that the tranny doesn't have a bolt on drivshaft yoke. Some truck applications use them. I am not sure a slip yoke will work where a bolt on was before.

    ------------------
    70 Camaro Z/28 with 461cu.in. BBC & OD Auto, 3.31 12 bolt posi.
     

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