Axle ratio?

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Jul 6, 2010 | 03:13 PM

67nukeford

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From: Omaha/Elkhorn, NE

Axle ratio?

Here's my dilemma. I'm swappping the front axle out of a 79 into my 67, for it's disc brakes. The tag is gone from the 79 axle. What I need to know is, can you tell axle ratio some other way, say from the donor truck's VIN? Need to know if it's the same gear ratio as the old axle. BTW, it's a Dana 44.

Thanks!

Jul 6, 2010 | 08:27 PM

NumberDummy

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From: Simi Valley, CA

No Ford VIN, regardless of the year (truck or not)...has the AXLE code info. It's listed separately on the Warranty Plate (1948/80). On the Certification Label, 1981 to date.

Ford rarely listed the front driving axle code within the AXLE code found on the Warranty Plate.

If the AXLE code found on the Warranty Plate is two digits, there is no front driving axle code.

If the AXLE code is three digits, the 3rd digit is related to the front axle, but in most cases, has to do if the truck had P/S or not.

Jul 6, 2010 | 09:23 PM

Fordzilla80

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From: Florida

You can do a few things to figure it out,none of which involve a vin.There's supposedly a number stamped on the front of the axle near the carrier.Decode this,and it should tell you what you have.Try Dana's website for more info.Or,you can do the whole spin the wheels and count the driveshaft turns.Or,you can pull the Diff and count the teeth on the ring and pinion gears.Or,the easiest way,is to look at the ring gear.The ratio is usually stamped on it.

Jul 6, 2010 | 09:42 PM

4x4jedi

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There are no stampings on the axle that give the ratio. The only way to be shure is to pop the cover and turn the ring until you find a code XX-XX. Divide the lower number by the higher and that's the ratio. The code is the tooth count on the ring and the pinion. It's usualy the last numbers after the part number.

Jul 7, 2010 | 01:14 PM

67nukeford

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From: Omaha/Elkhorn, NE

Thanks guys, I'll pop the cover later today and get those numbers!

Jul 23, 2010 | 09:43 PM

67nukeford

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From: Omaha/Elkhorn, NE

Okay, pulled the cover on the Dana that came out of the 79. Here are the numbers that are on the spool. Any idea which ones will tell me the ratio??

7 28 79 DANA 3/259 A3R52 42 12 980

Thanks!

Jul 23, 2010 | 10:11 PM

Ford_Six

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From: The Big, Oregon

if that 42 12 is the last of the main number series and is stamped as 42-12, then it's a 3.5 ratio gearset.
Here's a pic of a 4.10 gearset I have awaiting install- The 45-11 is the tooth count, and as stated by 4x4jedi is divided to find the ratio.

If your truck's ratio is different, you should be able to swap your whole carrier along with the ring and pinion to the new axle without too much trouble.
If there is a problem with your current carrier, double check the gear ratio as the carrier was different for 3.73 down and 3.92 up (numerically speaking).