More i think about it more i think your right. I keep confusing myself. The sensor is on the lower driveshaft. So it is spinning slower then the top one cause its going through the transfercase. In my datalogger is asks for differential ratio.. So i put in 21 whish is my final ratio but when i made a run it said i was spinning either 100mph or 10 mph i forget but it was way off.... So next time i just wrote in 6:80 (my differential ratio) and it would give me numbers like 30mph whitch is about right.

Maybe i'll just call Altronics again and let them walk me through it again.

thanks for the help guys!!

---

I forgot that you are running through a tranfer case
so the ratio would change