I came across these two short tutorials on how a mechanical voltage regulator functions in detail. Apparently there are two basic types depending on how the generator field winding is wired, type A and type B. Other than that, the two types are identical. I'm guessing Pilothouse Dodge trucks use something closer to type A. They explain how the three parts of a voltage regulator control charging the battery, how it prevents the battery from draining back to ground through the generator when generator voltage is low or zero, and how it prevents overcurrent and over overvoltage conditions from happening. Just good stuff to know.
Type A
Type B