Ram is using AAM axles in these trucks.
The front is a 9.25” unit and the rear with the HO is a 12.0” one.
The diffs are 3.73 on all SRW trucks. The front is open and the rear has a clutch style LSD.
Also, you appear to be pickup shopping but keep selecting the Cab and Chassis tag for your posts. Not a big deal, just pointing it out for the future.