I'm not sure I would agree with you about Jack's terminology, Lynne, I'm sorry to say. From the time I've spent around young men, roughnecks, rodeo people and rural people, I have to say that a certain percentage of them have nasty potty mouths. What's worse, it's like alcohol, the more you indulge in it, the more it takes to be effective. For some of these people, the F word is like saying "uh" or "you know" or "very."
Plus, young men's vehicles are thought to be female as ships are or hurricanes used to be. Jack calling his truck a c*nt is close to a term of endearment!! He probably imbued it with another layer of meaning, since he felt the oppression of what he saw as a female-dominated society, since Lureen sort of wore the pants in that household!