Differential and Transfer case

My oil change place tells me that the Transfer case fluid should be changed at 50,000 miles which is what my manual says, but then tells me my front and rear differential needs to be changed every 15,000 miles. I can't find anything about this in the book ??
p.s. I plan on having the dealership preform these items

False information as always from oil change places.:banghead: It's a good idea to change your ATF, xfer case and diffs before 50Kmi, but every 15K for the diffs is not necessary. I personally would perform these services myself as I have NO faith in kwiky-loobs.

G/luck
Joel