The Ford Barn

ahshoe · 05-20-2019, 09:25 PM

Is there an easy way to determine the gear ratio with the carrier and axles in the housing.I have a complete rear end that I would like to determine the ratio.I know how to do it with the carrier removed.but can't remember how and if it can be done in the housing.

miker98038 · 05-20-2019, 09:52 PM

Try this, note the difference between posi and non posi. Should get you close enough to look up the available factory ratios.

https://shiftsst.com/articles/how-to...ear-axle-ratio

Daves55Sedan · 05-20-2019, 10:06 PM

Jack up the rear tires off the ground. Put a chalk mark on the backside of a rear tire and get under the car near that tire so you can both see that chalk-mark and the driveshaft turning. Temporarily place a little magnet, or make a chalk-mark on the driveshaft near the rear universal joint. Now, rotate the rear tire one revolution while counting the number of times the driveshaft rotates.
Example: if it takes three revolutions of the driveshaft to get one complete tire rotation, you have a 3 to 1 gear ratio.

ahshoe · 05-21-2019, 05:20 PM

More info...it is an open rear end...rear end is off (out) of the car, with no tires on it.so ???

KULTULZ · 05-21-2019, 05:46 PM

Quote:

Originally Posted by ahshoe

More info...it is an open rear end...rear end is off (out) of the car, with no tires on it.so ???

Does the rear have a removable carrier or integral carrier? Either way just count the number of RG teeth and PINION teeth and divide to get the ratio. You may also be able to see ID NOS. on the gears and the tooth number(s) will be marked.

40cpe · 05-21-2019, 09:18 PM

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Foul one of the brake drums so it can't turn. Mark you pinion yoke and housing for reference. Mark your free drum with the backing plate. Turn your free drum TWO revolutions and count the tuns of the pinion yoke for your ratio.

05-20-2019, 09:25 PM	#1
ahshoe Senior Member Join Date: May 2010 Location: Eastern Iowa Posts: 350	Figuring out a gear ratio question Is there an easy way to determine the gear ratio with the carrier and axles in the housing.I have a complete rear end that I would like to determine the ratio.I know how to do it with the carrier removed.but can't remember how and if it can be done in the housing.

05-20-2019, 09:52 PM	#2
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,397	Re: Figuring out a gear ratio question Try this, note the difference between posi and non posi. Should get you close enough to look up the available factory ratios. https://shiftsst.com/articles/how-to...ear-axle-ratio

05-20-2019, 10:06 PM	#3
Daves55Sedan Senior Member Join Date: May 2010 Location: Granite City, Illinois Posts: 3,008	Re: Figuring out a gear ratio question Jack up the rear tires off the ground. Put a chalk mark on the backside of a rear tire and get under the car near that tire so you can both see that chalk-mark and the driveshaft turning. Temporarily place a little magnet, or make a chalk-mark on the driveshaft near the rear universal joint. Now, rotate the rear tire one revolution while counting the number of times the driveshaft rotates. Example: if it takes three revolutions of the driveshaft to get one complete tire rotation, you have a 3 to 1 gear ratio.

05-21-2019, 05:20 PM	#4
ahshoe Senior Member Join Date: May 2010 Location: Eastern Iowa Posts: 350	Re: Figuring out a gear ratio question More info...it is an open rear end...rear end is off (out) of the car, with no tires on it.so ???

05-21-2019, 09:18 PM	#6
40cpe Senior Member Join Date: May 2010 Location: Star, MS Posts: 4,024	Re: Figuring out a gear ratio question Sponsored Links (Register now to hide all advertisements) Foul one of the brake drums so it can't turn. Mark you pinion yoke and housing for reference. Mark your free drum with the backing plate. Turn your free drum TWO revolutions and count the tuns of the pinion yoke for your ratio.