Speedometer reading incorrect

jcborch

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I have a 2001 wrangler, the speedo is reading that I'm going 15 mph faster. Haven't really checked anything yet, just wanted to get a general idea of where to start. It does have a 3" rough country lift and tire size is 31x10.5xr15. Not sure if it just needs recalibrate due to the lift and tire size.
 
I have a 2001 wrangler, the speedo is reading that I'm going 15 mph faster. Haven't really checked anything yet, just wanted to get a general idea of where to start. It does have a 3" rough country lift and tire size is 31x10.5xr15. Not sure if it just needs recalibrate due to the lift and tire size.

You need to change the speedo gear in your Transfer Case to the correct number of teeth to accommodate the larger than stock tire size and gear ratio. It’s an easy 5 min swap.

https://www.quadratec.com/c/reference/jeep-speedometer-gear-tooth-chart
 
Here's how to swap the speedometer gear. It only takes a few minutes and you only need a 1/2" wrench. If the speedometer doesn't work after replacing the gear you probably just didn't rotate the speedometer gear housing far enough so the new smaller diameter speedometer gear meshes with its pinion gear located underneath it inside the transfer case. http://www.4x4xplor.com/speedo.html
 
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Reactions: 2001slvrstntj
Here's how to swap the speedometer gear. It only takes a few minutes and you only need a 1/2" wrench. If the speedometer doesn't work after replacing the gear you probably just didn't rotate the speedometer gear housing far enough so the new smaller diameter speedometer gear meshes with its pinion gear located underneath it inside the transfer case. http://www.4x4xplor.com/speedo.html

Thank you for the help. I will let ya know how it goes. It might be a moment till I can get this done but I will post back as soon as I can
 
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Reactions: Jerry Bransford
https://www.yellr.com/

Best money I spent. After having gears strip out due to SYE tolerances and #39 and higher gears being too large of a diameter to simply insert straight in, I bought the calibrator. The gear charts are not that accurate and you will be lucky to get it within a few mph. Using an Iphone GPS program, you can get it exact. And changing wheels is simple to reprogram.