Olek, leave the OBC test on while running and have your girl give you the reading when it does the weird radio shut off thing. If it spikes above 14 or below 12 it might be the Voltage Regulator on the alternator which I've seen some 4.8iS need to replace.

The transfer case codes are weird though, is there a separate control module for the Xdrive transfer case? - I do not have much experience as my '03 has the mechanical Xfer case

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2018 Ram 2500 6.7L Cummins 68RFE
19k miles -Bright White/Black - Big Horn Sport - Crew Cab Short Bed
2013 X5 35D (CEO's) - Born on 5/17/2013 -
82k miles - Alpine White/Cinnamon Brown/Premium Pkg, Sport Activity/Premium Pkg and Sound/20" Style 214/Running Boards