Texas CDL Inspecting Doubles and Triples

Begin with the tractor, then inspect each coupling and trailer in sequence. Confirm the correct trailer order, secure cargo, compatible heights, adequate clearance, and that no unit is leaning or damaged. More units create more failure points; do not skip repeated items.

Check mounting, platform, locking jaws, release handle, kingpin engagement, apron condition, and visible gap. The jaws must close around the kingpin shank, not the head. Confirm the release handle is secured and the trailer is supported correctly before the tug test.

Inspect the dolly frame, fifth wheel, pintle hook, drawbar eye, safety chains, air lines, electrical cable, tires, lights, and brakes. Secure the pintle hook and its locking device. Never stand between units while movement or rollback is possible.

Connect service and emergency lines correctly, secure glad hands, inspect seals, and prevent lines from rubbing, dragging, or being crushed. Attach electrical cables with enough slack for turns but not enough to contact the road. Open required shutoff valves and close the rear valves at the end of the combination.

Charge the full system and test leakage, trailer service brakes, emergency response, tractor protection, and air flow through the combination using the current handbook sequence. A failed valve or warning test requires correction before travel.

Verify landing gear is raised, doors and cargo are secure, lights and reflectors work, tires and wheels are sound, and every coupling has clearance through turns. Perform a controlled tug test and low-speed brake check before entering traffic.