The 'Kingpin' is:

The pin on the trailer that connects to the tractor's fifth wheel.. Section 6.4 (General Knowledge covers basic coupling): The kingpin is

The 'Kingpin' is:

ANSWER BREAKDOWN
  • A. Correct. Section 6.4 (General Knowledge covers basic coupling): The kingpin is the pin under the trailer that locks into the fifth wheel.
  • B. Incorrect. "The locking mechanism on the door." is not correct. Section 6.4 (General Knowledge covers basic coupling): The kingpin is the pin under the trailer that locks into the fifth wheel.
  • C. Incorrect. "A part of the engine." is not correct. Section 6.4 (General Knowledge covers basic coupling): The kingpin is the pin under the trailer that locks into the fifth wheel.
  • D. Incorrect. "The driver." is not correct. Section 6.4 (General Knowledge covers basic coupling): The kingpin is the pin under the trailer that locks into the fifth wheel.