All right I just got back from a longer test, which was also a good opportunity to test the 4WD, and the truck passed with flying colors.
Apart from stalling when I backed out of the driveway, it behaved just fine today. Here's the video. That should explain things better:
https://youtu.be/v7cZiP2S0qQ
So, this can rule some things out, right? What can this rule out?