Speedo Drive Gear Colour

Discussion in 'Got gears?' started by gstewart, Jul 2, 2019.

  1. gstewart

    gstewart Well-Known Member

    Can someone tell me what colour & # teeth the speedo drive gear is for my GS with the following info from the build sheet/gm documents and the part# on the seal& sleeve speed gear is 1362285 according to the parts book
    3.08 rear gear
    G78x14 orig tire size
    th350
    My unit is leaking where the speedo cable attaches to the "bullet". The small seal is probably defective as could also be the shaft. I removed the unit from the tranny & replaced the large o-ring as it had deteriorated & leaked. I got a used small seal for the speed shaft & i know the shaft was also marked. So it is now leaking.
    tkx
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Green 42 tooth DRIVEN gear ( 1362049), ONLY IF your transmission is the same one the car left the factory with (numbers matching)

    This info right out of the 1972 Buick Chassis Manual, page 40-90.

    1972SpeedoGearChart.jpg

    Working backward with the formula,

    https://www.tciauto.com/speedometer-gear-calculator

    G78-14 is 27.06" tall
    3.08 rear gear
    42 tooth DRIVEN gear

    The DRIVE gear would have been 18 teeth( Blue) on the ORIGINAL transmission.

    THM350SpeedoGears.JPG
     
    Last edited: Jul 2, 2019
  3. Dr. Roger

    Dr. Roger Stock enthusiast

    Yeah, you should pull out the driven gear and look inside to see what color the drive gear is first.
     
  4. BrunoD

    BrunoD Looking for Fast Eddie

    If anybody needs those gears,I have a few NOS still in stock.Gerry would have first choice,if he needs anything.Bruno.
     
  5. gstewart

    gstewart Well-Known Member

    I have the chassis manual but could not find the chart. Tkx for the chart..
     
  6. gstewart

    gstewart Well-Known Member

    I had the speedo gear out of the tranny, as I stated above but I could not remember the colour of the gear.
    I guess that I will have to crawl under the car to verify the part#, as per the master parts book, of the "bullet", then remove the bullet and verify gear colour.
    I am certain that I will need the gear as it was marked (will let u know Bruno).
    I also require the outer seal (orange in colour ?) - anyone have a source?.
    I really do not want to have to purchase the whole bullet, but if I have to I will.
    When I verify everything, I will let u guys know.
    I do know that different bullets use different gear shat diameters.
    Again, thx for all the help.
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

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