Is this an ST or a TH?

Discussion in 'The "Juice Box"' started by Kriz, Jun 21, 2021.

  1. Kriz

    Kriz Member

    I'm thinking it's a TH400
     

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  2. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    It's a 400. The st400 and th400 are the same trans, just a name change.
     
  3. Kriz

    Kriz Member

    Isn't the ST the switch pitch?
     
    Super Bald Menace likes this.
  4. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I don't think they all were. How many wires are on the plug going into the trans? That is an easy identifier. are you looking to order parts or just identify what you have? Buick kept the ST name for a few years in the beginning, the other makes called it the TH400 right off.
     
  5. Kriz

    Kriz Member

    At this point trying to identify it. It'll be sent off to a tranny shop in the coming months
     
  6. TrunkMonkey

    TrunkMonkey Well-Known Member

    ST is Buick's designation "Super Turbine" and the "ST" has nothing to do with the Variable Pitch (Switch Pitch) feature.

    The ST models, both 300 and 400 did have those that were Switch Pitch feature. (But other ST300 and ST400 models did not have Switch Pitch feature)

    As stated, it was Buick's "name" for the Turbo-Hydramatic models.

    BT 68 it is a 1968 "big car" with 430 engine. (I have a 430 and BT tranny out of a 968 4D Wildkitty setting in my garage, in the corner, keeping the mice from turning my cars into Condos)
     
    Max Damage likes this.
  7. Jim Weise

    Jim Weise EFI/DIS 482

    Trans tag is that of a 68 BT Non Variable pitch trans.

    That dual dimple pan, without the "Turbo Hydramatic" script was used from 68 to 72. It's getting to be rare, and is one that resto guys in the know search for, since it is correct for all GS and GSX cars of that era. If you replace it, I am sure someone on the board here would want it, don't throw it out, it looks to be unrusted and undamaged.

    All 400's from 65 to 67 were Variable Pitch transmissions. Not sure when the ST designation stopped, and the TH started.

    "Switch Pitch" is a term Kenne-Bell coined in the late 60's amd early 70's for the 65-7 transmissions, or any later TH unit that was equipped with the VP pump and input shaft.

    JW
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Technically, that is a Super Turbine 400, but as mentioned, it was Buick's name for the 400. A 1968 400 would have been fixed pitch as the Switch Pitch was only from 65-67. As far as when the 400 transmission's name changed, I say in 1969. My evidence comes from the Buick Chassis Manuals. In 1968, The manual says ST300 and ST400,
    1968.JPG

    In 1969, it is Turbo Hydra-Matic 350 and 400, but still Super Turbine 300,
    1969.JPG
     
    SpecialWagon65 likes this.
  9. SpecialWagon65

    SpecialWagon65 Ted Nagel

    Creeping towards GM ubiquitous corporate identity. Great answer Larry! Chassis manuals can be a source of knowledge and inspiration.
    Tis where I found out the 46000 series had a 4-speed. A grand spiral since then for me.
     
  10. Kriz

    Kriz Member

    Don't plan on throwing it out. It's going be rebuilt and used in a Skylark I'm building. This is my 1st journey out of the Chevy zone so I'm trying to learn. I do appreciate all the information!
     

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