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Spedometer reading to high

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I think my spedometer is reading to high. I changed out the gauge cluster. The donar truck was a auto 4.0L XJ and mine is a ba-10/5 with 3.55 gears. I have 245-70/16 on it.


I think the spedometer is reading to high, usually they read low because the tires are larger than stock size.


Has anyone ran across this? I am thinking about 10 mph off at 70mph.

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An MJ with a 4.0L and a 5-speed should have 3.07 gears. Did you change your gearing or axle(s)?


Also, your tires are 16" and those were never offered on the MJ, and 245/70-16 is oversized for a late model XJ. My wife's 2000 XJ came from the factory with 225/70-16 tires ... they are the same size as 225/75-15. So they are oversized, and as you note the speedo should read slow. But if you have 3.55 gears and the speedo drive gear still thinks you have the original 3.07 gears, that would make the speedo read higher than actual speed.


You need to pull the speedo drive gear, count the number of teeth, and compare it to the chart for your axle ratio and tire size.

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I thought so, how do I find out what kind of spedo gear I need? I did have 3.07 gears before, but that shouldn't mean anything for the trans right? I guess I can see it. Do they sell the right one I need?


What chart?

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here's the chart




calculate your USA measurement of the tire, and compare it to the chart, then shoot me a pm on which one you need. from all the jeeps I've parted out, I have rougly 20 speedo gears laying around, so chances are I have one.



the going rate for a speedo gear (new) is around $70, I sell them on naxja for $25 plus shipping, and they usually end up costing a base of $30 shipped.



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It looks like I need the 33 tooth one.


I have 3.55 rear end, ba/10 2wd trans, and 29.5 inch tires.




I changed the rear end, I used to have 3.07 gears and I am slowly converting to 4wd.


When I get a 4wd trans will the same gear work in the ax-15?


Let me know if you have one and I will buy it from you, Thanks!

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