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Unread 09-10-2001, 08:15 PM   #1
offctr
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Determining gear ratio question

How can I determine the gear ratio of an axle already out of the vehicle --no tags --dont want to start pulling the cover --etc fromthe revolutions of the yoke to the wheel
1 to 3/4 or wheel to yoke 1 to 1-1/2 can I calcualate the ratio if known to be within 3.07 to 4.88 range ????

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Unread 09-27-2001, 01:03 PM   #2
BaileyTJ
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if you know what truck it is out of you can try www.ring-pinion.com and click on gear calculator

HTH
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Unread 10-02-2001, 07:40 PM   #3
RodeoRob
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you can get a rough idea... jack up the car, spin the wheel one complete revolution and count how many rev's the driveshaft makes. for example, if you driveshaft spins 3 times for 1 turn of the wheel, you most likely have a 3.07 or something in that ballpark.

To be more exact, what you need to do is open the diff cover, count the teeth on the ring gear and count the teeth on the pinion, and divide the two numbers. there's your ratio.

-Rob
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Unread 10-03-2001, 04:19 PM   #4
Willis91YJ
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The axle ID number as well as the gear ratio should be stamped on the back side or the right tube. Look for a set of factory stamped numbers, the feds require them to be there before it leaves the factory, you may have to clean-off a few layers of grime to find'em but they're there!
Willis
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Unread 10-03-2001, 06:35 PM   #5
mytjnamedrex
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I tried the lift up tire and spin thing and it came out 1:1. I know this isnt possible so is there a trick? I put the car in N and my friend and i slowly spun the rear wheels in the same direction....everything was marked and i got 1:1. Its got 30" tires if that makes any difference.
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