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Old 09-13-2011, 02:18 PM   #1
Jynx
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Default Rear Differential

Is there a easy way of finding the gear ratio of a A rear end
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Old 09-13-2011, 02:38 PM   #2
RcT
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Default Re: Rear Differential

I just saw this the other day on here... mark one of the rear tires with chalk at the 6 o'clock position; remove the spark plugs; put the car in third gear; hand crank the car, in gear, until the rear marked wheel makes one complete revolution back to 6 o'clock. Count the number of engine revolutions to do this and there's your gearing.
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Old 09-13-2011, 03:06 PM   #3
Seth Swoboda
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Default Re: Rear Differential

Is there not a number stamping on the differential housing like the early V8's?
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Old 09-13-2011, 03:07 PM   #4
BRENT in 10-uh-C
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Default Re: Rear Differential

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Originally Posted by Seth Swoboda View Post
Is there not a number stamping on the differential housing like the early V8's?

Nope. The early differential housings that had a 3.70 were sometimes stamped but generally the "marking" is on the speedometer drive gear cap.
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Old 09-13-2011, 03:21 PM   #5
Fred K-OR
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Default Re: Rear Differential

Quote:
Originally Posted by RcT View Post
I just saw this the other day on here... mark one of the rear tires with chalk at the 6 o'clock position; remove the spark plugs; put the car in third gear; hand crank the car, in gear, until the rear marked wheel makes one complete revolution back to 6 o'clock. Count the number of engine revolutions to do this and there's your gearing.
I am confused again. I can see what you are doing but is there some formula that you use to compare the # of engine rev's to wheel rev's to get the rear end ratio????
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Old 09-13-2011, 03:50 PM   #6
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Default Re: Rear Differential

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Sure. If you turn the crankshaft over 3.7 times for one turn of the rear wheel, you have a 3.70 rear axle. It's that simple. Does that help?

Steve
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Old 09-13-2011, 06:05 PM   #7
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Default Re: Rear Differential

Thanks Steve.
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Old 09-13-2011, 06:28 PM   #8
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Default Re: Rear Differential

i was wondering weather there was a number on the housing ,,i knew about the speedo housing number......there are a couple for sale but i would like to know the ratio ...they are quite a drive to see them
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