Maybe mine is strange because it is a short wheelbase 3500? It's a 2015 6.0L 12 passenger. I have a 10.5" 14bolt full floater in another truck so I know the difference. Differential catalogs don't list it... like it doesn't exist. It has 14 bolts on the diff cover.

 

what is the cargo rating and gvwr? ... that is what they put in 1500's

 

GVWR: 9600 lbs. I'm not sure where that puts the cargo rating.
It isn't a 10-bolt. It's a 9.5" 14-bolt semi-floater by what it looks like to me. The springs look setup for the larger axle as the axle tubes neck down before going into the pumpkin.

 

I have a couple videos of the axle found in the 2003/2004/2005 model year 3500s marked as a 70S...mine is also 9600 lbs. You can clearly see it's a full floater when you pull the wheels off. I didn't film much of anything of the internals unfortunately. I always reach in the bottom searching for junk and if it's clean I just put it back together. It must be a tough axle because these vans are workhorses and you don't see many postings about them on the forums.