Ha Ha - you've only just entered the rabbit hole!
Save you some trouble. You will find that XL-12 is not available and Ford, without informing its consuming DIY customers in a clear manner, has now designated Mercon LV for use in your transfer case.

 

Im in flame mode again this morning.
I receive those infernal offers every month from the dealer I bought the truck from to trade my truck and forever be enslaved with a new car payment.
I receive notices for certain warranty TSB's from Ford to fix my freezing door locks....in middle GA where it rarely freezes.
Why cant Ford send me, maybe once a year if needed, changes to my operators manual, which would include recommended fluid specification changes?
Or Just let me subscribe and get digital updates.
Maybe I need to go find if they have updated the latest manual for my truck. Is it on the owner.ford website? If not, it should be. (EDIT: I checked. Their online manual still says XL-12 for the transfer case - FAIL!)

Flame off.

 

Well s=!+. I just looked and all the websites I looked at now say "superceded to Mercon LV." Too bad I still have 2 quarts of XL12 from my last fluid change....

My TC works flawlessly....so IDK

 

2 quarts is enough to do a change. I would use it up.