A 120-day preventive maintenance interval strikes the perfect balance for heavy-duty fleets—catching wear before failure while optimizing shop time. This comprehensive checklist covers everything from engine measurements to liftgate hydraulics, ensuring your trucks and tractors remain reliable year-round. Start your free inspection trial
120-Day PM Inspection
Truck & Tractor Preventive Maintenance Checklist
Maintenance Interval Overview
Powertrain Health
- Checking key engine components like mounts, belts, and fluid systems every 120 days prevents major engine failures and costly rebuilds.
Running Gear Integrity
- Detailed inspections of suspension (torque arms, king pins) and brakes (linings, drums) ensure the vehicle's core safety systems are road-worthy.
Auxiliary Systems
- Verifying the operation of liftgates, HVAC, and coupling devices (fifth wheels) ensures the truck is operationally ready for any job capability.
1. Cab & Walk-Around
Inspect safety devices, lighting, and driver environment:
Exterior Walk-Around
Cab Interior
Cab Systems
2. Engine & Chassis
Check powertrain components, fluid levels, and structural integrity:
Engine Compartment
Chassis & Suspension
Body & Drive
3. Brakes, Wheels & Liftgate
Inspect critical stopping power, tires, and hydraulic lift systems:
Brake System
Wheels & Tires
Liftgate Inspection
Why Standardize 120-Day PMs?
Fleet Rabbit App Benefits for Preventive Maintenance:
- ✓ Automatically schedule 120-day intervals based on last service date
- ✓ Track brake lining measurements to forecast replacement needs
- ✓ Monitor battery voltage trends on liftgates to prevent failures
- ✓ Create digital repair orders instantly for failed PM items
- ✓ Maintain a "cradle-to-grave" service history for every asset
- ✓ Ensure technicians follow the exact same procedure every time
Frequently Asked Questions
1. Is a 120-day interval sufficient for all trucks?
120 days is a standard interval for regional haulers. High-mileage OTR trucks may need more frequent service (e.g., 60-90 days), while low-usage vocational trucks might extend to 180 days. Always consult OEM guidelines.
2. Why is liftgate inspection included?
Liftgates are often overlooked until they fail. Including them in the truck's scheduled PM ensures batteries are charged, hydraulics are leak-free, and cables are safe, preventing delivery interruptions.
3. What should be recorded for brakes?
Don't just check "Pass". Record the actual remaining lining thickness (e.g., 10/32"). This data helps predict when a brake job will be needed, allowing you to budget and schedule it proactively.
4. Can I modify this checklist for trailers?
Yes, while this list covers tractors, many sections (Brakes, Lights, Suspension, Liftgate) apply to trailers. Fleet Rabbit allows you to create a dedicated "Trailer 120-Day PM" version easily.
Standardize 120-Day PMs
Ensure every vehicle receives the same high-quality preventive maintenance, every time.
