With the Dynamax setup I'm assuming locking the differential is just 100% engaging the rear mutli plate clutch assembly , so power is split 50% between front and rear axles - nothing more than SW programming. Saying 100% power can be sent to the rear axle is somewhat dubious as that would only happen if both front wheels have no traction and I don't think the system is really designed/intended to support full power output to the rear axle.Well said Dtech. We have had owners in the past that had to drive for one or more miles on roads that were not maintained during the winter (Not plowed) or that had ridiculously long driveways (Perhaps up to a mile long) because they wanted their home to be isolated from the neighbors and the (GM) AWD systems were not up to their expectations. They really needed a true 4WD vehicle or at the very least something more than the part time systems that GM offers. GM vehicles also do not offer the differential locking feature and I do find that to be very useful in urban driving in deep snow or very slippery conditions. Know that you truly need and purchase accordingly.
GM is known for doing some things on the cheap, so I wonder if some of their AWD driveline components can't take distributed power output for an extended period which you can do with the Dynamax so long as you don't exceed the speed constraint, but not sure what Dynamax does if anything when in lock and the vehicle is doing a lot turning.