70 GSX 4 speed question

Discussion in 'U-shift em' started by GSX-PKV, Jun 29, 2016.

  1. GSX-PKV

    GSX-PKV registered user

    I have a few questions: What 4 speed do a 4 speed GSX come with? A M21? What are the gear ratio's in the correct transmission? Thanks for any info. Paul
  2. Tri Shield

    Tri Shield Well-Known Member

    Hey Paul!!

    Unless I'm mistaken, the '70 GSX should have been equipped with the Muncie M21 close ratio gearbox with a 2.20 first gear. Pretty sure all Gran Sports with a 4 speed were so equipped.

  3. Marco

    Marco Well-Known Member

  4. GSX-PKV

    GSX-PKV registered user

    Thanks Marco. We are doing well and hope you are also. My car was a 4 speed car originally but the owner back in the 70s put in a Turbo 400. When I bought the car, I had a friend with a Super T10 and we put that in the car and it has been in the car 25 years. It started making some grinding noise so I want to restore the car to a transmission that would have been in it when new. A Muncie M21 I think would work well. I wonder if the shifter I use with that Super T10 will work with a M21. Have a great 4th! Paul
  5. GSX-PKV

    GSX-PKV registered user

    Thanks Rob!
  6. flynbuick

    flynbuick Guest

    Last edited by a moderator: Jun 29, 2016
  7. GSX-PKV

    GSX-PKV registered user

    Thanks for the info. Paul
  8. Tri Shield

    Tri Shield Well-Known Member

    No problem Paul! Perhaps we'll see you again soon at the Tuesday Evening shindig in MC.
  9. GSX-PKV

    GSX-PKV registered user

    See you there!
  10. oldsmobiledave

    oldsmobiledave Well-Known Member

    What were Buick & Oldsmobile thinking? The M-22 was long since available to Chevy & Pontiac yet neither Buick nor Olds offered the M-22 transmission when it was really needed in 1970.

    Oldsmobile offered the M-22 one year only in 1971. By then the compression drop already took a bite out of the torque that the standard & W-30 versions of the 455. Better late than never I guess.

    Then in 1972 & 1973 ONLY the M-20 was available in an Olds even with the optional 3.73 gears (my 72 W-30 was so equipped with M-20 & 3.73 gears).

    Question....Did Buick offer the M-22 transmission in any year before it was made obsolete by GM in 1974?
  11. BadBrad

    BadBrad Got 4-speed?

  12. GSX-PKV

    GSX-PKV registered user

    I found a guy who will build me a M21 with the proper casting numbers. Does anyone know the casting numbers for a 70 car for the case and tailshaft. Thanks for any info. Paul
  13. flynbuick

    flynbuick Guest

    see post #6 above re the TCS switch and the tail shaft. Dennis M will likely have those parts and maybe the speedo adaptor.

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