After coupling, how much space should be between the upper and lower fifth wheel?

None.. Section 6.4: There should be no space (no daylight) between the plates.

After coupling, how much space should be between the upper and lower fifth wheel?

ANSWER BREAKDOWN
  • A. Correct. There should be no space (no daylight) between the plates.
  • B. Incorrect. "1 inch." is not correct. There should be no space (no daylight) between the plates.
  • C. Incorrect. "2 inches." is not correct. There should be no space (no daylight) between the plates.
  • D. Incorrect. "It depends on the load." is not correct. There should be no space (no daylight) between the plates.