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Gear Ratio Question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by RAY, Jan 8, 2001.

  1. RAY

    RAY 1/2 ton status Premium Member

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    Does anyone know what the standard or base ratio was for a 10 bolt in '84? Also, I jacked up one of the wheels to find out the tire to drive shaft turn ratio, when I did this I got a 2 wheel turns to 2 3/4 driveshaft turns. Which I don't think makes much sense. If you have any info about this I would appreciate it.
    Thanks
    RAY
     
  2. rock.monkey

    rock.monkey 1/2 ton status

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    take your VIN. number to your local GM dealer, go to the parts dept. and have them look it up. They can tell you everything you need to know(as long as it's the original diff.)

    Bill Innes
    88' Jimmy
    [​IMG]
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    I'd be willing to bet it was 3.08. Now that is if it meets this criteria: 305, AC, 700R4, 4wd. The glove box or fender RPO tag will likely tell you, although you may end up with the informative "standard ratio" code ; ) It will be one of the codes that starts with "G", as in G80, which is "posi"

    Dorian
    My K5 and Chev/Olds links: <A target="_blank" HREF=http://yeagerd.home.mindspring.com/index2.html>http://yeagerd.home.mindspring.com/index2.html</A>
     
  4. RAY

    RAY 1/2 ton status Premium Member

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    The guy how owned it before me removed the glove box code sheet, but kept the options sheet.
     
  5. 6.2Blazer

    6.2Blazer 1/2 ton status

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    When you do the "turn the wheel and count the driveshaft revolutions" test, if you only turn one wheel you need to multiply the number of driveshaft revolutions by 2.
    In your case you have 2 tire revolutions to 2.75 driveshaft revolutions. Multiply 2.75 by 2, which equals 5.5, and then divide that by the 2 tire revolutions....and well, that equals approxiamately 2.75 and a 2.73 ratio was available from GM during that time period.
    Just as a side note, normally you would only turn the tire 1 revolution and then count the number of driveshaft revolutions....since you turned the tire 2 revolutions you actually deleted the need to do any math (I had honestly never thought of doing it that way until now).
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    My 81 Jimmy came with those gears [​IMG] and 33's.
    I'd be turning 1800 Rpm on the freeway, and it was a dog. Those were the first things to go. [​IMG]

    Rene

    [​IMG]
     

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