Found this on the 2500 press release
Suspension:
Heavy Duty trucks generally have a suspension equipped for constant, heavy payloads. A byproduct of that is a harsher ride when unloaded. To combat that Ram is using Frequency Response Damping (FRD) shocks on all four corners. The valves of an FRD shock automatically adjust for the type of vertical wheel input, allowing the Ram Heavy Duty to have a stiffer suspension feel for handling and a supple suspension feel on rough terrain. Engineers added progressive springs and upgraded bushings to the suspension system, including the exclusive five-link coil design on Ram 2500, providing better load-carrying characteristics and improved articulation over obstacles when compared to a leaf-spring system.
A class-exclusive Active-Level rear air suspension is available on both the Ram 2500 and Ram 3500 and includes some ingenious features. Controlled via an in-cab mounted toggle switch you can put the rear air suspension into bed lowering mode to lower the rear of the truck for easier loading or trailer hookup, normal/payload mode or a trailer-tow mode.
The 2019 Ram 2500 uses two air bags to replace the coil springs. Load capacity is not sacrificed, and the Ram 2500’s best-in-class ride and handling gets even better, crushing the competition with two doses of engineering innovation (five-link coil with an air suspension option).