If you are looking to drive American trucks in ETS2 1.40, you generally need a "Truck Conversion" mod.
: Large portions of the German road network were completely rebuilt with modern assets and realistic junctions. AMERICAN TRUCK PACK FOR ETS2 1.40
: Ensure your mod version is specifically tagged for 1.40+. Versions designed for 1.39 or older will have broken headlights and flat textures due to the lighting engine change. If you are looking to drive American trucks in ETS2 1
The most significant part of the SCS Software 1.40 Update was the complete revamp of the lighting system. Versions designed for 1
Beyond the visuals, ETS2 1.40 focused on bringing older map areas up to modern standards:
: High-dynamic-range skyboxes were added to provide more realistic weather transitions and sunset/sunrise effects.
: The "ATS Truck Pack for ETS2" by various modders allows you to purchase Kenworth, Peterbilt, and Mack trucks directly from ETS2 dealerships (usually UK or specialized dealers).