Hey, I discovered that the GTG mod has been deleted from repository. T-Series Expansion Pack gone? | BeamNG
It’s because it overwrited vanilla assets, which is against repo guidelines (or something like that) So now the full version will be on the forums and there will be a lite version on the repo.
Or there’s a big feature they’re still working on. Or alternatively they don’t have too much to show off.
I'm reverting to this answer, as I accidentally deleted my post. Gregory had overlooked the possibility that his mod was using a feature that wasn't supposed to be used at the moment. Afterwards, he's not entirely sure, he just put the idea on the table.
I can't find any center axle driving the steerable rear axle from the front, so my guess is it's electronic. Ooops, never really noticed that! I thought it was some kind of bug that never got ironed out!!