CDL Class A Pre-Trip Inspection: The Complete 2026 Walk-Around

The pre-trip inspection trips up more CDL Class A candidates than any other part of the skills test — not because it’s hard, but because applicants try to memorize a script without understanding what they’re actually looking at. The updated road test makes things a little easier, but it still demands that you name every safety-critical part and confirm its condition out loud.

Here’s a complete walk-around of a Class A tractor-trailer in the order most instructors teach it. Use it as a template, not a script — every truck is slightly different, and your examiner will expect you to point to what’s actually in front of you.

Front of the tractor: lights and ground check

Start where the examiner first sees you — at the front bumper.

• Clearance lights, headlights, turn signals, high beams — all working, proper color, lenses and covers mounted securely with no damage.
• Ground underneath — no puddles, no dripping fluid from the engine or transmission.
• Vehicle stance — not leaning left/right or front/back (a lean signals a suspension problem).

Then pop the hood. Latch it on both sides before you let go.

Under the hood: the three fluids and the steering system

Three fluids, every time, in plain language:

While you’re in there, verify:

• Hoses — no leaks, no cracks, mounted securely.
• Power steering box — securely mounted, no damage, no missing/loose nuts or bolts.
• Steering linkage (arm, link, rod) — not worn or cracked; joints and sockets tight; no missing cotter keys.

Tip: The exact wording your examiner accepts varies by state. Stick to the basics — securely mounted, not leaking, not damaged, no missing parts — and you’ll get credit on every section.

Tires, rims and brakes

Move to the steer tire. This is one of the most heavily weighted sections of the test.

• Tread depth — minimum 4/32” on steer axle, 2/32” on every other axle.
• Tread wear — even, no cuts or damage; sidewalls free of bulges or bubbles.
• Inflation — typically 90–100 PSI (check with a gauge if asked).
• Valve stem and cap — not leaking, securely mounted.
• Rim — not welded, bent, or damaged; bolt holes not elongated.
• Lug nuts and studs — all present, no rust trails or shiny threads (signs of looseness), studs not distorted.

For the brakes behind the tire:

• Brake hoses and lines — securely mounted, no leaks, cuts, or frays.
• Brake drum/disc — free from contaminants between drum and shoes (or between disc and pads).

If you want a deeper dive into how the brake system itself works, our CDL Air Brakes Explained guide covers every PSI number you’ll be quizzed on.

Suspension components

Stay at the steer axle and call out the suspension.

• Leaf springs — those flat metal bars; not missing, shifted, cracked, or broken.
• Spring hangers/mounts — securely mounted, no loose or missing nuts/bolts.
• Shock absorbers — securely mounted, not damaged, not leaking.
• Bushings — securely mounted.

Down the side: lights, mirrors, fuel and battery

Walk down the driver’s side of the tractor and call out:

1. Turn signal/clearance lights and reflectors — proper color, securely mounted, no damage.
2. Mirrors (or “traffic monitoring devices” per the FMCSA’s CDL Manual language) — securely mounted, no loose or broken fittings.
3. Fuel tank (and DEF tank if equipped) — securely mounted, cap on tight, no leaks from the tank or lines.
4. Battery box — door closed properly, batteries secure inside, no excessive corrosion, cables tightly connected.

Between the tractor and trailer

This is where most applicants lose points by rushing. There are three distinct topics to cover.

Frame and cross members

The frame is the long metal beam running under the tractor and trailer. Confirm: no cracks, holes, broken welds, or damaged cross members on the tractor or trailer; nothing wrong with the trailer floor.

Air and electric lines (3 things, every time)

Fifth wheel and coupling

This is the section examiners listen for hardest. You don’t have to crawl under — just name everything:

• Fifth wheel skid plate — properly lubricated, no cracks or breaks, securely mounted.
• Kingpin — not cracked, bent, or damaged.
• Apron (bottom of the trailer) — not bent or cracked.
• Gap — no gap between the fifth wheel and the apron.
• Locking jaws — fully closed around the kingpin, no play, no gap.
• Release arm — in the engaged position with the safety latch in place.

Remember: Every item on the pre-trip inspection traces back to a section of the official CDL Manual — primarily Section 2 (Driving Safely) and Section 11 (Combination Vehicles). If you understand why you’re checking something, you won’t freeze when the examiner phrases a prompt differently.

Trailer: landing gear, tandems, rear

Move out to the trailer.

• Landing gear — fully raised, no damage, no missing parts; support frame secure, shoes good, crank handle locked in place; enough clearance between landing gear and the rear axle.
• Reflectors and lights along the trailer — proper color, secure, working.
• Tandem release pins/lever — pins securely seated, no missing parts (only if your trailer has sliding tandems).
• Rear of the trailer — clearance lights, brake lights, reflective tape, mud flaps; door locked and operational.

You don’t have to inspect the rear trailer tire unless the examiner asks — but in real-world driving, always check it. Trailer tires take the worst beating on tight turns and rough lots.

Common mistakes that fail the pre-trip

For the in-cab portion that follows the walk-around (parking brake, service brake, and the seven-step air brake check), see our CDL Air Brake Check Walkthrough. And if you’re still deciding which CDL class you actually need, our CDL Classes A, B, C Explained breaks it down.

Practice the pre-trip the way you’ll be tested

Reading a checklist isn’t the same as standing in front of a truck and naming every part out loud under pressure. The fastest way to lock this in is repetition with explanations that connect each item back to the CDL Manual.

Our CDL Test app is built for exactly that — comprehensive practice covering the General Knowledge test, the Pre-trip Inspection question bank, and every endorsement. Each question links back to its CDL Manual section so you’re not just memorizing — you’re learning why the answer is correct.

It’s part of our suite of 1200+ questions across three focused apps (CDL, HazMat, and Air Brakes) — designed to mirror the format and difficulty of the real DMV exam.

Start free right now with a CDL practice quiz →