You have to install ETS 2 from the beginning, than upgrade to 1.4.1 to 1.4.8 there You buy the Tcab and make a savegame in Your existing profile, after that upgrade including Your profile with savegame Tcab, after that You can buy and play, also You can change the Tcab by name and skin, only mark in Your mod list the changed Tcab.
Please read first before installing! To paint sunvisor in the same color go to garage and choose special paint, meke truck Black (JPS skin) and buy. This has NO effect on the rest of the truck