Hey team. I realize this is an old thread I dug up, but it was what came up when I came straight here and was searching for "4wd auto", specifically for HD Rams. If you google, the 1500 discussions dominate and create too much noise to sift through.
From what I read in the owner's manual, and on here, it confirms there is no AWD or 4WD-auto mode on the HD's. Only on half tons. My current F150 is my first 4x4 vehicle and it does have 4WD-auto (4A) and will send power to all wheels as it feels necessary. There is even a power distribution screen you can watch the ratio of front/rear power when accelerating or taking off, until it usually settles to RWD when cruising.
Now, since my (on order) 3500 will be my first truck with deliberate 4H and 4L, I'm curious if its a good idea just to occasionally exercise the front drive so it doesn't go unused for super long periods of time? Like is it bad to never engage the front axle and hubs for several months or thousands of miles? I could very easily just engage it in a straight line on my street leaving home just to get some exercise in, then disable it again. Just not sure if that's pointless or not.