Sample pre-trip inspection of tractor-trailer units

Engine compartment (engine off)

Oil level

Coolant level

Power steering fluid

Engine compartment belts (not more than ¾ in (1.9 cm) play at center of belt)

Emergency equipment

Check for spare electrical fuses.

Check for three red reflective triangles, six fuses or three liquid burning flares.

Check for a properly charged and rated fire extinguisher (5 B:C or more).

Cab check & engine start

Depress clutch, if equipped. Place gearshift lever in neutral (or park, for automatic transmissions). Start engine, then release clutch slowly if equipped.

Oil pressure gauge

Temperature gauge

Air gauge, build air pressure to governor cut-out, roughly 120-140 psi (827-140 kpa).

Ammeter/voltmeter

Mirrors should be clean and adjusted properly from the inside.

Windshield should be clean with no obstructions, or damage to the glass.

Check for excessive play by turning steering wheel back and forth. Play should not exceed ten degrees.

Check that wiper arms and blades are secure, not damaged, and operate smoothly.
If equipped, windshield washers must operate correctly.

Horn

Climate, including heat, defrost, and air-conditioning, controls function

Seat belt

Parking brake check

Interior lights and indicators

Test that dash indicators work when corresponding lights are turned on:

• Left turn signal

• Right turn signal

• Four-way emergency flashers

• High beam headlight

• Anti-lock braking system (ABS) indicator

• Courtesy/map light

Air brake check (if equipped)

• Pressure drop not more than 3 psi (20.6 kpa kg) in one minute

• Low air warning not less than 60 psi (414 kpa)

• Parking brake applies when pressure drops below 40 psi (276 kpa)

• Service brakes side pull test

External inspections

• Fuel tank, including system cap

• Exhaust system

• Frame damage

• Splash guards

• Door latches

Steering & suspension components check

• Steering box/hoses

• Steering linkage

• Springs/air/torque

• Shock absorbers

• Trailer suspension

Brakes (Including trailer)

• Slack adjustors

• Brake chambers

• Brake air lines

• Brake linings

Wheels, tires (Including trailer)

• Rims undamaged

• Tire thread depth, 4/32 in (3.175 mm) steering, 2/32 in (1.5875 mm) all others

• Tire pressure

• Hub seals

• Lug nuts

• Wheel spacers

Lights and indicators (Including trailer)

Using a spotter, or a reflective surface, to verify that the following lights operate:

• Left turn signal

• Right turn signal

• Four-way emergency flashers

• High beam headlight

• Brake light

• Reverse light

• Low beams

• High beams

• Body marker and clearance lights

• Auxiliary lighting, such as fog lamps, load lights, etc.

Trailer items

In addition to the braking, suspension, and lighting above, the following should be checked:

Trailer ladders and cat walks condition

Hitch release lever function

5th wheel jaws, fully closed around king pin

5th wheel skid plate grease

5th wheel slider pins intact

Verify chain and tie downs are secured in rack

Check delivery hose securement (if equipped)

Check refrigeration unit operation (if equipped)