Transmissions and Drivetrain Need help with your trans? Problems with your axle?

Gear ratio question

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Old 05-16-2008, 06:48 PM
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Gear ratio question

I know theres a simple formula to figure out the gear ratio and I cannot seem to figure it out. With one full rotation of the tire, I get approx. 1 3/4 turn of the driveshaft.
Old 05-16-2008, 07:45 PM
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Re: Gear ratio question

its a bit more precise if you rotate the tire 5 or 10 times and count the driveshaft. divide the two. exp. 5 spins of the driveshaft divided by 2 spins of the tire is a 2.5 ratio

you need to spin wheel more, from what you give you come up with a 1.75:1 ratio, which is far from, what it is.

keep on spinning
Old 07-13-2008, 04:28 PM
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Re: Gear ratio question

Alright so I finally got to doing this. So with 5 full rotations of the wheels I only got 8 and 3/4 rotation of the driveshaft... I am very un-happy with my current situation.

Somethings not right. But I counted correctly I am sure of it
Old 07-26-2008, 03:01 PM
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Re: Gear ratio question

Any thoughts? Another thing...

I know the gear is poor because at 75 mph i am only at 2,500 rpms
Old 07-27-2008, 04:00 PM
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Re: Gear ratio question

=(
Old 07-27-2008, 04:47 PM
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Re: Gear ratio question

I've done it 2 ways. For posi rears, just one rotation of the tires should give 2.5-3.5 rotations of the driveshaft; meaning the gear ratio is 2.55:1 up to 3.42:1. It's the same for a non-posi axle, but only let one tire rotate, and make it go 2 rotations.
----------
My guess is that you have a 3.42:1 because that 1.75 is far too close to being half your gear ratio.

Last edited by fast82z; 07-27-2008 at 04:51 PM. Reason: Automerged Doublepost
Old 07-27-2008, 05:02 PM
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Re: Gear ratio question

Originally Posted by stevenb
Any thoughts? Another thing...

I know the gear is poor because at 75 mph i am only at 2,500 rpms
at 60mph, are you at 2K rpm? that is where I am with my T5 and 3.42 gears.
Old 07-27-2008, 06:59 PM
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Re: Gear ratio question

its time you just pull the cover off and count teeth, its not working for you any other way, and im sure the gear oil is in need of changing anyway.
Old 07-29-2008, 05:02 PM
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Re: Gear ratio question

Originally Posted by Zepher
at 60mph, are you at 2K rpm? that is where I am with my T5 and 3.42 gears.
Yes
Old 07-29-2008, 05:24 PM
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Re: Gear ratio question

Originally Posted by //<86TA>\\
its time you just pull the cover off and count teeth, its not working for you any other way, and im sure the gear oil is in need of changing anyway.
Save yourself the counting the gear ratio is stamped on the od of the dr gear.
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