Rear End Ratio Identification

[dewilson11]

Can anyone help me with identify what gear ratio I have in my 1972 F250 Crewcab? There is no tag on the rear end and all I found on the gears inside is the following 3 24 75 32503 A3E56 46-18

[69FLATBED]

There is a way you can count the revolutions of the tires and divide them into the pinion revolutions or vise-versa... It's been so long since i've done it i cant remember. I used to have a dentside 4x4 with a odd 3.50 ratio and could never find the ratio's in my mudding days. I'm sure someone can lead you in the right direction.

[bill69f100]

I had the same problem on mine when I bought it. I jacked the rear up, took off the left wheel. I marked the driveline and the drum so the marks were lined up with each other. I turned the drum and counted the rotation. For 1 rotation of the drum I had close to 3.5 turns of the driveline. Another way is a lot of work. take the diff out and count the teeth on the pinion and ring gear and divide one number into the other. I don't remeber which but, the end result will give you 3.00, 3.27, 3.50.

[PhantomoftheBumpside]

IF the rear end is original, then the info should be on your Warranty Tag (VIN) on the door...

Find the code at the end of the 2nd line on your tag and check it against the decoder page http://www.fordification.com/tech/VIN72.htm

[michael69]

Seen you have it opened up. Count number of teeth on pinion and the number of teeth on the ring gear. Then divide ring gear count by pinion count. That will give you the ratio.

[67 428 F250]

If you have open diff, just jack up one side, mark the tire and driveline at the bottom, turn tire 1 revolution and watch how many time the driveline turned, limited slip diff, lift both tires but no need to pull tires, drums and wheels turn at the same rate.