ST300 Transmission Input Shafts All The Same??

Discussion in 'The "Juice Box"' started by '65softtop4, Jul 5, 2021.

  1. '65softtop4

    '65softtop4 Well-Known Member

    I need an input shaft for a '65 ST300 in my '65 Gran Sport. Are the shafts interchangeable from
    '64 Pontiac ST300 to '65 Buick ST300?
    I have not a clue about auto trans.
     
  2. 436'd Skylark

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

    Depends on if the Buick 300 is a switch pitch. Pontiac didn't offer that..
     
  3. '65softtop4

    '65softtop4 Well-Known Member

    How do I identify if its an s.p. or not?
     
  4. '65softtop4

    '65softtop4 Well-Known Member

    Its not a switch pitch.
     
  5. telriv

    telriv Founders Club Member

    I have a '66 Skylark GS trans. complete with original converter.
    $350.00 & you could take a road trip to Ct. & pick it up.

    Tom T>
     
  6. wkillgs

    wkillgs Gold Level Contributor

  7. LARRY70GS

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

    FixedvsSwitchPitch.jpg
    Fixed Pitch on left, Switch Pitch on right. Focus on the stator splines. The stator splines on the fixed pitch shaft are twice as long as the switch pitch stator splines.
     
  8. '65softtop4

    '65softtop4 Well-Known Member

    Thanks guys. Now all I have to do is find one.
     
  9. '65softtop4

    '65softtop4 Well-Known Member

    Here is a picture of the shaft out of the transmission.

    123_1.jpg
     
  10. BrunoD

    BrunoD Looking for Fast Eddie

    I have 2 -300 switch pitch trans you could one3 or both have for a very reasonable price.You might also need the torque converter ,just look at those splines also.And I have a 12 inch converter .
     
  11. '65softtop4

    '65softtop4 Well-Known Member

    I have several torque converters with varying stalls. What are we talking on a trans?
    Are you close to gsfred?
     
  12. DaWildcat

    DaWildcat Platinum Level Contributor

    You just have to be bit careful, here. Over the years and among the different makes, some are variable pitch, others not (fixed pitch).

    A variable pitch trans needs a variable pitch converter, and a fixed pitch trans needs a fixed pitch converter. No mixing of the two either way.

    Devon
     
  13. '65softtop4

    '65softtop4 Well-Known Member

    Hi Devon,
    Appreciate the info. I will be sure to match when time comes.
     
  14. BrunoD

    BrunoD Looking for Fast Eddie

    As I stated,I have 2 switch pitch transmission and a 12 inch SP torque converter.We are talking about switch pitch trainy's,why would I sell you something different? And Fred does live near me[about 2 hours north.I live about 1/2 hour from NYC,he's close to 1.1/2 hours from NYC. Bruno.
     
  15. 436'd Skylark

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

    Isn't the input shaft hollow on the SP? I thought there was a rod that travelled through it that activated the SP?
     
  16. '65softtop4

    '65softtop4 Well-Known Member

    These transmissions are foreign to me. 4 speeds I understand. Automatics, I have no idea.
    That's why I'm thankful for everyone's help with this.
     
  17. LARRY70GS

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

    No, but fluid flows through it. I believe there is a piston concentric with the converter hub that is pressurized to move the stator blades. Maybe the Dynaflow had a mechanical linkage? Not sure.
     
  18. 436'd Skylark

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

    I was picturing a rod similar to a late model lock up converter
     
  19. '65softtop4

    '65softtop4 Well-Known Member

    Is the switch pitch activated electronically?
     
  20. LARRY70GS

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

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