Hello I am looking for information on what I would need to change the pinion gears in my ford 9 inch. Can I figure out if it is a 28 or 31 spline by looking at it?

 

I wouldnt know for sure, but you could just zap the pinion yoke off and count them

 

http://www.kevinstang.com/Ninecase.htm This might help.

 

You may want to try the drivetrain forum first. This is the 335 series engine forum.

Anyway, the year and what the axle is under will make a difference as to what is inside of it. After that the easiest way is going to be pulling out an axle shaft and start counting.