8lug and they said it was 2500 but to be honest it was a rusted out pile so i did not stay to look at it long i just popped one of the rear center caps off and could see it was not the ff. Maybe they were lyeing it also had the 6.o v8 but i know some of the 1500 could be had with the 6.0 aswell. So your pretty confident that all of the 2007-2013 suburban 2500 have the ff? Im just having a hard time believing because i asked this question on several forums and am getting conflicting answers

if it was 2007 and newer and 8 lug, its ff.

you can remove the axle flange bolts and slide the axle out with all the vehicle weight sitting on the wheel...

https://i.ytimg.com/vi/EMxfb9X3ywE/maxresdefault.jpg