During coupling system inspection, which items should you check?

During coupling system inspection, which items should you check?

• A. The fifth wheel for cracks, breaks, security, and grease.
• B. The kingpin for excessive cracks, bending, or wear.
• C. The differential for loose wire connections.
• D. A and B.

Answer: (D)

In coupling system inspection you focus on the parts that actually connect the tractor to the trailer and keep that connection secure. The fifth wheel must be free of cracks or breaks, securely mounted, and adequately lubricated with grease so it can couple and articulate safely without binding or slipping. The kingpin needs to be free from excessive cracks, bending, or wear because damage there can prevent a secure lock and allow unwanted trailer movement or detachment. The differential is part of the drivetrain, not the coupling system, so it isn’t checked during this inspection. So you inspect both the fifth wheel and the kingpin to ensure a safe, reliable coupling.

In coupling system inspection you focus on the parts that actually connect the tractor to the trailer and keep that connection secure. The fifth wheel must be free of cracks or breaks, securely mounted, and adequately lubricated with grease so it can couple and articulate safely without binding or slipping. The kingpin needs to be free from excessive cracks, bending, or wear because damage there can prevent a secure lock and allow unwanted trailer movement or detachment. The differential is part of the drivetrain, not the coupling system, so it isn’t checked during this inspection. So you inspect both the fifth wheel and the kingpin to ensure a safe, reliable coupling.