does any body have the part number for the gear reduction box that treads into the transfer case and then the speed sensor threads into it?

 

X2, I need that number as well, either that or a source, I plan going to 35" tires do I need to change calibrators? (don't mean to hijack but I am in the same boat )

 

I dont have the part number, but when Iwas lookign for one, I found it was a dealer only part. and I beleive it was around $80 if I remember correctly

To change the gear ratio DC, you'll have to change teh Drive Pinion gear, not the gear reducer.
If you have a competent parts guy at your local dealership, they can look up the correct one by rear end ratio and tire size..