what rear end gears do i have?

chris91

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Tire size can affect mph too so going by that can be off. The way I do it is to jack the rear up and have someone spin the rear wheel 10 times while you are counting the revolutions of the driveshaft. 37 = 3.73, 41 = 4.10 etc.
 

CC'S95GT

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both tires HAVE to spin together, at the same speed, and in the same direction.
 

lutter94

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What size tires? I would have to guess 3.27's. But only one way to find out for sure.....read above....:)
 

ScottyDsntKnow

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Google "rpm calculator" it will be the first result. Scroll to the bottom of the page and use that calculator trying out different gears. Stock tires are 245/45/17 which are 25.7" tall. Final drive for the T-5 is .68 and for the AODE its .70 so you should be able to figure it out via this method.

As long as your speedometer is right that is. I'd verify your speedometer with a GPS speedometer app first because you would not be the first person who bought a car with gears and the PO didn't put a new gear/use a speedcal or they used that stupid white 23 tooth gear that is not meant for Fords.
 

whiplash473

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Easy rough guess way: Jack up the ass end, put a mark on the drive shaft and a mark on your tire. Spin the tire until the drive shaft makes a complate revolution back to where it started. Count the amount of times the tire rotated and that'll give you a pretty close estimate.

Let's face it, there's only so many ratios it could be, assuming it's the stock axle.
 

CC'S95GT

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Easy rough guess way: Jack up the ass end, put a mark on the drive shaft and a mark on your tire. Spin the tire until the drive shaft makes a complate revolution back to where it started. Count the amount of times the tire rotated and that'll give you a pretty close estimate.

Let's face it, there's only so many ratios it could be, assuming it's the stock axle.

ya got it backward sport. 1 revolution of the tires and count how many times the DS rotates.
DS 3.5 turns= 3:55, 3 3/4 turns = 3:73, just over 4 turns 4:10 etc.
 

whiplash473

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ya got it backward sport. 1 revolution of the tires and count how many times the DS rotates.
DS 3.5 turns= 3:55, 3 3/4 turns = 3:73, just over 4 turns 4:10 etc.
Whoops, you're right. CC to the rescue once again, thanks.
 

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