Connecting a Tractor and Semitrailer

The Foundation of Safe Combination Driving

Knowing how to couple and uncouple correctly is basic to the safe operation of combination vehicles. An improper connection poses extreme hazards on the highway. Incorrect coupling and uncoupling can be very dangerous, leading to dropped trailers or severe equipment damage. Because design differences exist between trucks, drivers must learn the specific coupling details for the rigs they operate.

Before beginning any maneuvers, confirm that the area around the vehicle is clear. Cargo inside the trailer must be secured against movement caused by coupling, as the jolt of backing under can shift loose freight. To prevent the trailer from rolling away, trailer wheels must be chocked or trailer spring brakes must be applied prior to coupling.

You must thoroughly inspect both the tractor and trailer equipment. Check the trailer kingpin to ensure it is not bent or broken. Inspect the fifth wheel for damaged or missing parts, and verify that the mounting to the tractor is secure with no cracks in the frame. If the rig uses a sliding fifth wheel, it must be locked in place prior to coupling. Additionally, the fifth wheel plate must be greased as required to prevent steering problems caused by friction. Prepare the fifth wheel by verifying that the plate is tilted down toward the rear of the tractor, the jaws are open, and the safety unlocking handle is in the automatic lock position.