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Gear Ratio

Discussion in 'Flat Fender Tech' started by c-wooley, Dec 30, 2008.

  1. Dec 30, 2008
    c-wooley

    c-wooley New Member

    Joined:
    Mar 5, 2008
    Messages:
    6
    If my axles have no tags on them what is the best way to determine what the gear ratio is. I thougt you could jack up one tire and count the rotations of the drive shaft compared to the tire. But when I do this my tire turns one revolution compared to about two and a half on the drive shaft. That can't be right can it. Could I be doing this wrong?
     
    c-wooley, Dec 30, 2008
    #1
  2. Dec 30, 2008
    Homebrew2

    Homebrew2 Member

    Dunlap, CA
    Joined:
    Aug 17, 2007
    Messages:
    511
    As I understand it, because you [obviously] have an "open" differential, you need to double your rev count which puts the ratio near 5:1 ... 4.88:1 is probably close to what you have :)
     
    Homebrew2, Dec 30, 2008
    #2
  3. Dec 30, 2008
    EricM

    EricM Active Member

    Southern California
    Joined:
    Dec 19, 2007
    Messages:
    1,019
    There's a good little writeup in the tech library

    http://www.earlycj5.com/tech/axle/#fifteen

     
    EricM, Dec 30, 2008
    #3
  4. Dec 30, 2008
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    4,275
    It could also be 5.38:1.

    For the cost of a pan gasket & some fresh gear oil I would pull the rear cover & have a looksee. It's not a difficult job at all, and more often than not an old jeep can stand to have the diff. oil changed.
     
    w3srl, Dec 30, 2008
    #4
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