So, you may wanna rework the physics. Despite my best efforts, i was unable to lose any cargo until later engine upgrades.
Milk also breaks the game like nulledabyss stated. A milk run with four full trailers to New York took me almost 5 minutes because the frames dropped massively every time i hit a bump.
Another issue i noticed is that despite engine upgrades and minimal cargo, the truck struggled a lot on uphill sections like in Whitehorse. Not only that, it also struggled going downhill, as if it only detected the slope and disregarded gravity entirely. There is also a pothole part in Whitehorse that I was unable to get across, because my trailer just got stuck.
I made a quick screenshot of the problem part:
I am going full throttle with a lvl 5 engine, it is not letting me go farther