i just changed from 3.45's to 4.10's and my speedo is reading to high. 70 by the end of 3rd. BS! my question is what size gear and how big of a PITA is it to swap speedo gears?

thanks

 

the answer was a 35 spline gear with 33 inch tires and 4.10 gears. super easy install. if the tcase bolt comes out it takes about 5 min to swap gears. if you get lucky like me you have to remove your t-case and drill and tap the dang thing.

 

Sigh. Easy solution.

Do you have a smart phone? Turn on GPS. Drive down the highway at 80 mph, ACCORDING TO THE PHONE GPS.

Now write down what your speedometer says. Divide and see how far you are off.

I just got my spedometer working for the first time after I build a chevy to dodge conversion cable to find I have 25% taller gearing than the OEM dodge with 3.55. haha.