Used truck inspection checklist

What to bring

• A bright flashlightFor looking under the truck and into the engine bay.
• A small magnetIt won't stick to body filler, so it finds hidden rust or crash repairs.
• Paper towels or a ragTo check fluid colors on the dipsticks.
• A cheap OBD-II code reader (1996 and newer)Shows trouble codes, including ones that were recently cleared.
• Something to lie on, and clothes you can get dirty
• A friend, if you canThey can watch for smoke and leaks while you drive or rev the engine.

Paperwork and history

• The VIN on the dash, the driver's door sticker and the title all match
• The title is clean and in the seller's nameWatch for salvage, rebuilt, flood or lien notes.
• Open recalls checked at nhtsa.gov/recalls using the VINUnfixed recalls are free to repair at a dealer, but you'll want to know.
• A vehicle history report reviewedLook for accidents, odometer issues and how many owners.
• Service records, especially oil changes and transmission service
• You've asked how the truck was used: towing, plowing, off-road or commutingHeavy towing and plowing wear out transmissions, brakes and front ends faster.

Walkaround and body

• Panel gaps are even and paint color matches on every panelUneven gaps or mismatched paint point to crash repair.
• Magnet sticks on the lower doors, rocker panels, wheel arches and bed sides
• Cab corners, rocker panels and bed floor checked for rust or bubbling paint
• Tires worn evenly, with matching brandsWorn inside or outside edges mean alignment or front-end problems.
• Tire date codes checked (the last 4 digits are week and year)Tires older than about 6 years should be replaced, even with good tread.
• Hitch receiver and bed checked for heavy towing wear or a gooseneck/5th-wheel hitchA sign the truck has worked hard. That's not bad, but it should be priced in.
• All lights work, including the brake lights and trailer plug

Frame and underneath

Use the flashlight. Rust is the one problem that can make a truck not worth fixing.

• Frame rails checked end to end for flaking, holes or soft spotsSurface rust is normal. Scaling, holes or rot are not. Tap suspicious spots with a screwdriver handle.
• No welding, patches or fresh undercoating hiding the frameFresh undercoating on an older truck can be covering rust.
• Frame isn't bent or kinked, especially behind the cab and at the hitch
• Spring hangers, shackles and crossmembers are solid
• No leaks dripping from the engine, transmission, transfer case or axles
• Exhaust intact with no heavy rust or missing partsOn diesels, ask whether emissions parts were removed. That can be illegal and cause inspection problems.

Engine (start it cold)

Ask the seller not to start the truck before you arrive. A cold start shows problems that a warm engine hides. Feel the hood when you get there.

• Engine starts easily with no long cranking
• No knocking, ticking or loud rattles at startup or idle
• Exhaust smoke is light and clears quicklyLasting blue smoke means burning oil, white means coolant or unburned fuel, and heavy black means a rich mixture or injector trouble.
• No warning lights stay on after startup, including check engine
• Code reader shows no stored codes and that the monitors are "ready"Monitors that aren't ready can mean codes were just cleared to hide a problem.
• Oil on the dipstick is not milky, sludgy or grittyMilky oil can mean coolant is mixing with the oil.
• Coolant is at the right level with no oil film or rusty color
• Belts and hoses aren't cracked, and there are no fresh leaks around the engine

Diesel trucks

• With the oil filler cap off and the engine idling, only light vapor comes outStrong puffing or smoke ("blow-by") can mean worn piston rings.
• Engine idles smoothly with no misses or rough runningRough idle can point to injector problems, which are expensive on many diesels.
• No fuel or oil around the injectors or turbo
• Turbo spools up smoothly with no abnormal whistling, grinding or smoke under acceleration
• On 2008 and newer: no exhaust or DEF warnings, and you've asked about DPF cleaning historyEmissions systems (DPF, EGR, DEF) are a common costly repair on modern diesels.
• You know whether the engine is stock, tuned or "deleted"Tuning and emissions deletes can void warranties, fail inspections and may be illegal where you live.

Transmission, transfer case and axles

• Transmission fluid is red or pink and doesn't smell burnt (if it has a dipstick)
• Shifts into drive and reverse without a hard clunk or long delay
• 4WD engages in 4-high and 4-low, and the dash light comes onTest on gravel or dirt, not dry pavement, to avoid binding.
• No grinding or clunking when 4WD engages or disengages
• Manual: the clutch engages smoothly and doesn't slip under load
• U-joints and driveshafts have no play when you twist them by hand (engine off)

Suspension and steering

Heavy-duty trucks with solid front axles can develop a violent front-end shake after hitting bumps ("death wobble"). The usual causes are worn steering and suspension parts.

• Truck sits level side to side and front to back
• With the engine running, little free play when you rock the steering wheel back and forth
• Have a friend rock the wheel while you watch the track bar, tie rods and ball joints for movement
• Shocks aren't leaking, and the truck doesn't keep bouncing after you push down on a corner
• Leaf springs aren't cracked, sagging or missing leaves
• Steering box and power steering lines aren't leaking

Brakes and brake lines

• Steel brake lines along the frame aren't heavily rusted or swollenRusted lines can burst without warning. This is common on older trucks in salt states.
• Rubber brake hoses at each wheel aren't cracked or bulging
• Rotors aren't deeply grooved, and there's pad material left
• Brake fluid is clear to amber, not dark brown
• Parking brake holds the truck on a slope

Lifted or modified trucks

A well-done lift is fine. A cheap or poorly installed one causes handling problems, wears parts fast, and can be unsafe.

• You know the lift brand and who installed it, and there's a receiptKnown brands and shop installs are a good sign. "My buddy did it" deserves a closer look.
• It's a real suspension lift, or you know it's only spacers or blocksSpacers and tall rear blocks are cheaper and can affect handling and axle wrap.
• Track bar and steering geometry were corrected for the lift (drop brackets or an adjustable track bar)Skipping this is a common cause of wandering steering and death wobble.
• Brake lines are long enough at full droop and aren't stretched or kinkedLifts often need longer brake lines.
• Driveshaft angles look reasonable, with no vibration on the test drive
• Larger tires: the speedometer was recalibrated and the gearing suits the tire size
• No cut or hacked wiring from aftermarket lights, winches or electronics

Inside the cab

• No musty smell, damp carpet or water linesSigns of leaks or flood damage.
• Heat, A/C, windows, locks, mirrors and 4WD switches all work
• Seat and pedal wear matches the mileage
• All dash gauges work, including the trans temp gauge if it has one

Test drive

Drive at least 20 minutes if you can, on city streets, a highway and a rough road.

• Accelerates smoothly with no hesitation, surging or excessive smoke
• Transmission shifts smoothly up and down, with no slipping or flaring RPM
• Drives straight on the highway and the steering wheel is centered
• No shake or vibration at highway speed or after bumpsShaking after a bump can be the start of death wobble.
• Brakes stop straight with no pulling, grinding or pulsing pedal
• No clunks over bumps or when turning sharply
• No whining or humming that changes with speedCan mean worn axle bearings or gears.
• Engine temperature stays steady

After the drive

• Look underneath again for new drips
• Check for warning lights or new codes with the reader
• For a truck you're serious about, get a pre-purchase inspection from an independent mechanicUsually around $100–200, and the best money you'll spend on a used truck. Pick a diesel shop for a diesel.