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Medium Duty Trucks

Medium-duty Box Truck (including refrigerated) Pre-purchase Inspection Checklist

A guided, do-it-yourself pre-purchase inspection checklist for used medium-duty box trucks, Class 3 to 7 (about 12,000 to 33,000 lb GVWR), gas or diesel. Covers Isuzu NPR and NQR, Chevrolet and GMC cab-overs, Hino, Mitsubishi Fuso, Ford E-450 cutaways, Freightliner M2, International and similar trucks. No mechanic needed: each check tells you what to look for and what counts as a fail, from the frame, engine, transmission and brakes to the cargo box, roll-up door, refrigeration unit and liftgate. Includes air-brake tests, diesel exhaust checks and known problems by make. Not for dump, flatbed or utility trucks: use our Medium-Duty Dump, Flatbed and Utility Truck checklist for those.

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$29.00

90 days of access. Inspect and compare up to 12 items of this type.

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What you get

  • No mechanic needed. Most checks need only your eyes, a flashlight and a tire gauge; a few optional deeper checks go further if you have the tools or bring in a mechanic.
  • A guided checklist written for this kind of purchase: every question says what to look for and what counts as a fail. Ready to use the moment you pay.
  • Inspect on your phone: answers save as you go, with photos and notes on any question.
  • Send it to a mechanic, supervisor, colleague, or employee by text or email. They need no account.
  • A report that puts the problems first, with photos, times and location.
  • Inspect and compare up to 12 vehicles, machines or trailers of the same type with one purchase, side by side, before you decide.

Known problems, checked

Comes with a guide to the known problems and red flags to watch for.

How it works

  1. Choose a checklistPick the one that matches what you are buying, and pay by card. No account to set up first.
  2. Add what you are inspectingEnter the item, the asking price and where it is. Add as many as you are considering.
  3. Inspect it, or send itWork through the checklist on your phone, or send it to a mechanic, supervisor, colleague, or employee to do for you.
  4. Read the report and compareSee the problems first, with photos. Put your options side by side and decide.

What it covers 107 questions

  • Records and Identity8 questions
  • Cab, Frame and Body Mounting6 questions
  • Engine12 questions
  • Diesel Exhaust and Emissions4 questions
  • Transmission and Drivetrain8 questions
  • Steering, Suspension and Brakes11 questions
  • Wheels and Tires9 questions
  • Electrical, Electronics and Cab9 questions
  • Cargo Box8 questions
  • Refrigerated Box1 question
  • Road Test5 questions
  • Liftgate5 questions
  • Air Brakes5 questions
  • Cab-Over Trucks1 question
  • Isuzu N-Series and Chevrolet or GMC Cab-Over Only3 questions
  • Hino Only3 questions
  • Mitsubishi Fuso Only2 questions
  • Ford E-450 and F-Series Only2 questions
  • Freightliner M2 Only2 questions
  • International Only2 questions
  • Final Review1 question

A sample of the questions

  • VIN matches everywhere
  • Frame rust and cracks
  • Engine oil level and condition
  • Exhaust filter warnings and regeneration
  • Gear engagement when cold
  • Ride height and lean
  • Tire tread depth
  • Batteries and resting voltage

This is a sample. The full checklist is yours when you buy.

Before You Start

You don't need a mechanic or to be a mechanic. Most questions need only your eyes, a flashlight and a few low-cost tools, and each one tells you exactly what to do and what counts as a fail.

Allow about two and a half hours, including a 20-minute road test. Longer if you do the deeper checks or the truck has a liftgate or air brakes.

For medium-duty box trucks, Class 3 to 7 (about 12,000 to 33,000 lb GVWR), gas or diesel: Isuzu N-Series, Chevrolet and GMC LCF and W-Series, Hino, Mitsubishi Fuso, Ford E-450 cutaways and F-650/750, Freightliner M2, International, and similar. Not for refrigerated box performance, dump, flatbed or electric trucks.

In the US, a truck rated over 26,000 lb needs a CDL to drive, including on the road test. Check the rating before you go.

Before you go, ask the seller to:

  • Leave the engine cold. Some checks need a cold start.
  • Have the title, keys, service records and the last annual inspection report ready.
  • Park the truck on level ground where you can walk all the way around it and open the rear door and liftgate.
  • Agree a road-test route, and access for a mechanic if you are bringing one.

Go in daylight, with the parking brake on and the wheels blocked.

Never get under the truck while it is held up only by a jack, under a tilted cab that is not on its safety lock, or under a liftgate platform.

Answer every question as indicated. Skip the sections for equipment or a make the truck does not have (answer Not applicable).

Questions marked "Deeper check" are optional extras that need special tools. Skip any you can't do, or ask a mechanic to do them.

Write readings in the note, and add a photo of anything that fails.

Bring (all available at an auto parts store for well under $100 in total):

  • A flashlight
  • A tape measure and painter's tape
  • A tread depth gauge and a tire pressure gauge with a dual-wheel head
  • A basic multimeter, for the battery and charging voltage
  • A code reader (a heavy-duty one for Class 6 and 7 diesels with a round 9-pin port)
  • A stick thermometer, for the air conditioning vents
  • A screwdriver, for tapping rusty frame and floor areas
  • A clean card or stiff paper, for the blow-by test
  • A watch or phone timer, for the air brake and liftgate tests
  • White paper towels and gloves
  • A helper, for the lights, the cold start and the steering checks
Tools for a Deeper Inspection (Optional)

You don't need any of these to use this checklist. For the questions marked "Deeper check", or if you bring in a mechanic, these are the tools needed, as well as those in Before You Start:

  • A floor jack and jack stands rated for the truck's front axle weight, for the kingpin and wheel bearing check
  • A scan tool that reads this make's engine, transmission and exhaust filter data (heavy-duty for Class 6 and 7 diesels)
  • A cooling system pressure tester with adapters for this truck
  • A ruler marked in sixteenths of an inch, for air brake pushrod travel
Sources and Standards
  • FieldDone pre-purchase inspection protocol for medium-duty trucks (October 2026)
  • Your truck's own owner's manual, body builder's manual and liftgate manual, matched to its VIN and serial numbers
  • US Federal Motor Carrier Safety Regulations, annual inspection standards (49 CFR Part 396, Appendix A)
  • Commercial driver's licence manual (your state or province), air brake inspection section
  • NHTSA recall lookup
  • Canadian Council of Motor Transport Administrators, National Safety Code
  • Isuzu TruckService portal and Body Builder Guides
  • Isuzu Vehicle Health Report
  • Maxon liftgate manuals