I think I'm losing my mind....

I have checked several $42 XDFs along with some disassemblies, and can not find the parameter for rear end gear ratio.

I need to set up a chip for someone I know that had an '8747 go bad, and will be replacing it with a '7747, and need to make sure that everything is set correctly for the vehicle, and a big one being the gear ratio so that vehicle speed is correct. I'm sure I've had this parameter before, but unless it's named something odd, that I don't remember (It has been a bunch of years since I've worked with anything '7747), so am I missing something here or is it just not there, and requires every speed/gear based parameter to be set individually?