It is extremely rare that I find a theme that fits a truck perfectly. Aside from the four obvious ones, the only truck that I say directly hits bullseye is Junkyard Dog. A theme like that for a truck like that is just perfect.
If there are any trucks that I can say need a change ASAP, it'd be the following:
Predator - Generic, annoying, and a failed attempt at dubstep
Monster Mutt Rottweiler - Same as Predator, minus the dubstep, but even more annoying
Black Stallion - The theme itself isn't bad. In fact, as a song alone, it's really good. It's just that to me, it sounds like it would fit more on Gunslinger.