If slack is observed during the tug test after coupling, what is the recommended action?

• A. Make corrections to the connection
• B. Ignore the slack and continue
• C. Move the tractor away until the slack disappears
• D. Apply the parking brake and continue

Answer: (A)

Slack in the tug test means the coupling isn’t fully secure. The tug test checks that the tractor and trailer are firmly connected, with no play between them. When you feel or hear slack, you must correct the connection before proceeding. This usually means backing up and reseating the kingpin in the fifth wheel, ensuring the locking jaws are fully closed and engaged, and that air and electrical lines are properly connected. Once the connection is rechecked and tightened, perform the tug test again to confirm there is no remaining slack. Ignoring the slack or continuing with it can allow the trailer to detach or shift during movement, creating a serious safety risk.