Kenworth Truck Trailer Inspection Checklist

Trailer Inspection Information

This inspection checklist is designed to help Kenworth truck operators thoroughly inspect trailers prior to operation. Regular trailer inspections are essential for safety, preventing breakdowns, and meeting regulatory requirements. The Federal Motor Carrier Safety Administration (FMCSA) requires pre-trip inspections of both truck and trailer. Use this checklist alongside your tractor inspection to ensure complete compliance and safety.

Trailer Coupling Inspection Procedures

Follow these inspection procedures to ensure safe and secure coupling between your Kenworth truck and trailer.

Fifth Wheel Connection

Check fifth wheel for proper positioning
Verify fifth wheel is securely mounted
Inspect for cracks in fifth wheel assembly
Check that kingpin is properly engaged
Verify locking jaws are fully closed
Confirm release handle is in locked position
Ensure safety latch is engaged
Check for proper lubrication

Trailer Kingpin

Inspect kingpin for wear or damage
Check for proper kingpin length
Verify kingpin is securely mounted
Inspect mounting plate for cracks
Check for proper apron plate condition
Verify no gap between upper/lower fifth wheel
Ensure trailer is level when coupled
Test connection with tug test

Air & Electrical Connections

Check air lines for proper connection
Inspect air lines for damage or leaks
Verify gladhands are sealed correctly
Check electrical cable for secure connection
Inspect electrical connector pins
Verify cable has adequate slack
Check for abrasions or cuts in cables
Ensure cables are properly suspended

Landing Gear

Verify landing gear is fully retracted
Check for damaged or bent components
Ensure landing gear handle is secured
Inspect mounting bolts for tightness
Check for adequate clearance
Verify smooth operation in both directions
Check for proper lubrication
Ensure landing gear pads are intact

Trailer Body Inspection Checklist

Verify these critical trailer components as part of your pre-trip inspection.

Trailer Frame

Inspect frame rails for cracks
Check crossmembers for damage
Verify no damage to trailer sills
Look for signs of impact damage
Check for twisted or bent frame
Inspect welds for cracks
Check for corrosion or rust damage
Verify frame is not sagging

Trailer Body

Check trailer sides for damage
Inspect roof for holes or damage
Verify doors open and close properly
Check door seals for integrity
Inspect floor for damage or weakness
Check body for protruding objects
Verify all rivets/fasteners are secure
Check overall structural integrity

Cargo Securement

Check tie-down points for integrity
Inspect cargo bars/straps/chains
Verify adequate number of tie-downs
Check working load limit ratings
Inspect load for proper distribution
Verify cargo is blocked and braced
Check securement for proper tension
Verify proper edge protection is used

Trailer Markings

Check for proper DOT markings
Verify company markings are present
Inspect reflective tape condition
Check for proper placement of reflectors
Verify license plate is secure and visible
Check registration decal validity
Verify USDOT number is displayed
Inspect placards (if required)

Undercarriage

Inspect for loose or hanging items
Check for damage to underside
Verify mud flaps are properly mounted
Check for dragging components
Inspect for excessive corrosion
Look for signs of recent impact
Check for fluid leaks
Verify proper ground clearance

Specialized Equipment

Inspect trailer-mounted generators
Check reefer unit operation (if equipped)
Verify lift gate functionality (if equipped)
Test hydraulic systems (if applicable)
Check roll-up door function (if equipped)
Inspect sliding tandem operation
Verify load ramp condition (if equipped)
Test trailer auxiliary systems

Trailer Roof

Check for damage or punctures
Look for sagging areas
Inspect roof bows for damage
Check corner caps for security
Verify roof seams are intact
Look for signs of water damage
Check roof sheet securement
Inspect roof-to-side rail connections

Trailer Doors

Verify doors open and close properly
Check door hinges for security
Inspect door seals for damage
Check locking mechanisms
Verify door hold-backs function
Inspect door panels for damage
Check door frame integrity
Verify door hardware is secure

Trailer Running Gear Inspection

Inspect these critical running gear components to ensure safe trailer operation.

Trailer Suspension

Check air suspension height
Inspect air bags for damage or leaks
Verify leaf springs for cracks or shifting
Check spring hangers and shackles
Inspect torque arms and bushings
Check U-bolts for tightness
Verify axle alignment
Inspect shock absorbers for leaks

Trailer Axles

Check for bent or damaged axles
Inspect axle alignment
Verify axle spacing
Check axle-to-suspension mounting
Inspect spindles for damage
Check for signs of overheating
Verify proper axle tracking
Inspect axle capacity rating

Trailer Wheels

Check for cracked or bent rims
Verify all lug nuts are present and tight
Inspect for rust trails (loose lugs)
Check for elongated stud holes
Verify proper matching of dual wheels
Inspect valve stems and caps
Check for debris between dual wheels
Verify proper wheel spacers (if used)

Trailer Tires

Check tire pressure (100-105 PSI typical)
Inspect tread depth (minimum 2/32")
Look for cuts or bulges in sidewalls
Check for uneven wear patterns
Verify matching tire sizes on axle
Look for signs of rubbing or contact
Check for regrooved tires on steering axle
Inspect for proper tire rating

Wheel Bearings

Check for signs of leaking seals
Verify proper lubrication
Look for blue discoloration (overheating)
Check for excessive wheel end play
Listen for unusual noises when rotating
Inspect hub oil level (if applicable)
Check bearing adjustment
Verify hub cap is secure

Sliding Tandem

Check slider rails for damage
Verify locking pins engage properly
Ensure all pins are fully engaged
Check slide mechanism operation
Inspect for bent components
Verify proper position for weight distribution
Check slider stop blocks
Ensure release handle is secured

Trailer Brakes

Check brake drums/rotors for cracks
Inspect brake linings/pads for wear
Verify slack adjuster travel
Check brake chambers for damage
Inspect air lines for leaks/chafing
Verify antilock brake system operation
Test parking brake function
Check brake adjustment

Trailer Air System

Check for audible air leaks
Verify air pressure maintains properly
Inspect gladhand seals
Check service and emergency lines
Verify trailer air tanks drain properly
Test emergency breakaway system
Check brake application and release
Verify proper air pressure drop rate

Trailer Electrical System Inspection

Verify the following electrical components as part of your trailer inspection.

Trailer Lighting

Check all tail lights
Verify brake lights function
Test left and right turn signals
Check clearance/marker lights
Verify license plate light
Inspect identification lights (top 3)
Check ABS indicator light
Verify all lights are securely mounted

Electrical Wiring

Inspect 7-way electrical connector
Check for damaged or frayed wiring
Verify proper cable support
Inspect junction boxes (if present)
Check for exposed wiring
Verify no dragging electrical components
Test trailer auxiliary power (if equipped)
Check for proper grounding

Reflectors & Conspicuity

Check side reflectors (amber front, red rear)
Verify rear reflectors are present
Inspect conspicuity tape condition
Check reflective tape on sides (50% coverage)
Verify reflective tape on rear (continuous)
Check lower rear reflective marking
Inspect reflectors for damage
Verify proper reflector placement

ABS System

Check ABS indicator light function
Verify ABS electrical connector
Inspect ABS ECU mounting
Check wheel speed sensors
Inspect sensor wiring for damage
Verify proper ABS valve operation
Test ABS warning system
Check for stored fault codes

Specialized Trailer Type Inspections

Use these specific inspection procedures based on trailer type.

Refrigerated Trailer

Check reefer unit operation
Verify fuel level in reefer unit
Inspect refrigeration lines
Check temperature settings
Verify air chute condition
Inspect door seals for integrity
Check drain holes for blockage
Verify reefer data recording system

Flatbed Trailer

Check deck condition
Inspect stake pockets
Verify winch bar and straps
Check headboard integrity
Inspect chain boxes
Verify D-rings and tie-down points
Check rub rails condition
Inspect coil packages (if equipped)

Tanker Trailer

Check tank shell for damage
Inspect all valves and fittings
Verify manhole covers are secure
Check vapor recovery system
Inspect baffles (listen for movement)
Verify proper placarding
Check loading/unloading equipment
Inspect pressure relief devices

Lowboy/Equipment Trailer

Check ramps and hydraulic systems
Inspect deck condition
Verify outriggers (if equipped)
Check beavertail and approach plate
Inspect load securement points
Verify gooseneck connection
Check flip axle operation (if equipped)
Inspect hydraulic lines for leaks

Coupling & Uncoupling Procedures

Follow these procedures for safe coupling and uncoupling operations.

Coupling Procedure

Inspect fifth wheel for damage
Check fifth wheel is in unlocked position
Verify trailer height is correct
Back slowly under trailer
Connect at approximately 75% of kingpin length
Set tractor brakes and exit cab
Check fifth wheel jaws have engaged kingpin
Connect air lines and electrical cable
Raise landing gear fully
Secure landing gear handle
Perform pull test to verify connection
Remove wheel chocks

Uncoupling Procedure

Park on level ground
Set tractor parking brakes
Place wheel chocks under trailer wheels
Lower landing gear until it contacts ground
Adjust landing gear for proper trailer support
Disconnect air and electrical lines
Secure air lines to tractor
Unlock fifth wheel release handle
Pull tractor slowly from under trailer
Check that trailer is stable on landing gear
Verify air supply is disconnected
Inspect trailer security before leaving

Sliding Tandem Adjustment

Park on level, solid surface
Set tractor and trailer brakes
Check desired position for legal weight
Release slider locking pins
Move tractor slowly to desired position
Verify pins are aligned with holes
Set trailer brakes to help pins engage
Ensure all pins are fully engaged
Secure slider release handle
Visually check all pins
Perform tug test to verify pins engaged
Check weight distribution after adjustment

Emergency Procedures

Test trailer emergency breakaway system
Verify breakaway cable is secured
Check breakaway battery charge
Test manual trailer brake valve
Verify air pressure builds properly
Check low air warning devices
Test parking brake application
Verify spring brake operation
Ensure proper brake adjustment
Check ABS warning light operation
Verify emergency equipment is present
Review emergency response procedures

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