Semi-Truck Preventive Maintenance Checklist

The four PM tiers represent escalating service depth at progressively longer intervals. PM-A every 10,000-15,000 miles is basic service: oil and filter change, tire and brake visual inspection, fluid levels, belt and hose visual, lights, chassis lube. PM-B every 25,000-30,000 miles adds: fuel filter replacement, air filter check, coolant condition test, suspension components, wheel bearings, basic alignment check. PM-C every 50,000-60,000 miles adds: transmission fluid service, differential fluid change, brake overhaul, comprehensive electrical system test. PM-D every 100,000 miles or annually adds: DOT annual inspection items per §396.17, DPF cleaning service, complete emission system check, drivetrain comprehensive service. The tiers are cumulative — PM-D includes all PM-A through PM-C items. Multi-trigger scheduling determines which tier is due at any time based on mileage, engine hours, or calendar — whichever triggers first. Start your free trial to deploy the 4-tier framework.

Semi-trucks should receive structured preventive maintenance at multiple cadences simultaneously. PM-A approximately every 10,000-15,000 miles, PM-B every 25,000-30,000 miles, PM-C every 50,000-60,000 miles, PM-D every 100,000 miles or once annually (whichever comes first). Severe-duty operations (construction, refuse, mining, high-idle) should reduce these intervals 30-50%. High-idle operations with 30%+ idle time should track engine hours primarily — typically 250-400 hours between PM-A intervals. Multi-trigger scheduling runs all three triggers (mileage + hours + calendar) simultaneously, with PM service triggered by whichever fires first. Driver-level checks happen daily (pre-trip), weekly (deeper visual), and monthly (deeper assessment) between formal PM cycles. The full annual DOT periodic inspection under §396.17 is required within 12 months and typically aligns with PM-D.

A complete PM covers 8 system categories regardless of tier (with depth varying). System 1 — Engine and oil: oil and filter change, air filter, valve cover, mounts. System 2 — Cooling: coolant condition, radiator, water pump, thermostat, hoses. System 3 — Fuel: fuel filter, water separator, lines, tank, pump pressure. System 4 — Drivetrain and transmission: transmission fluid, differential, U-joints, slip yoke, AMT diagnostics. System 5 — Brakes and air system: lining thickness, slack adjusters, air leak test, air dryer, ABS sensors. System 6 — Tires, wheels, and suspension: pressure, tread, bearings, lug torque, springs, alignment. System 7 — Electrical and battery: battery load test, alternator output, starter draw, lights, wiring. System 8 — Chassis and aftertreatment: DPF, DEF, exhaust, frame, fifth wheel, kingpin. The depth of each system varies by PM tier — PM-A is visual and basic service, PM-D is comprehensive teardown. Contact our sales team for the complete checklist deployment.

PM costs vary significantly by tier, fleet specifics, and whether work is done in-house or outsourced. Typical 2026 ranges for outsourced PM service: PM-A $200-$400 per truck (basic service, parts + labor); PM-B $400-$800; PM-C $1,200-$2,500 (comprehensive with transmission and differential service); PM-D $2,000-$4,000+ (major service with DOT annual). In-house labor reduces these significantly. Annual PM program cost typically runs $2,500-$5,000 per truck depending on annual mileage and duty cycle. Compare to: average emergency repair cost $1,500-$5,000 plus $760/day downtime (ATRI data), tow charges $500-$1,500 if roadside, and CSA score impact. The math consistently favors structured PM by 3-5× over reactive maintenance. The 20-30% maintenance cost reduction documented in PM deployments is net of the PM investment itself.

Three categories of consequence. (1) Direct breakdown cost: components that fail without PM intervention cost 150-200% more to repair as emergency service vs scheduled. A $400 PM-A oil change skipped becomes a $5,000-$8,000 engine repair when contaminated oil destroys bearings. (2) Compliance exposure: FMCSA §396.3 requires systematic maintenance, and audits look for evidence of structured PM programs. Carriers without PM documentation face CSA Vehicle Maintenance BASIC violations, raising scores and triggering further audit attention. The 2026 CSA overhaul weights OOS violations at 2× severity. (3) Resale and operational impact: trucks without PM history sell at significant discount, equipment lifespan drops 20-40%, and driver retention correlates strongly with vehicle reliability. The combined economic case for disciplined PM is overwhelming — 300-500% 24-month ROI is documented across thousands of deployments. Sign up free to deploy structured PM scheduling.

It depends on fleet size, geographic footprint, and operational complexity. Fleets under 20 trucks typically outsource because the volume doesn't justify dedicated shop space, technician hires, and parts inventory. Fleets of 50-100+ trucks often benefit from in-house PM for routine work (PM-A, PM-B) while outsourcing specialty work (transmission rebuilds, major engine work). Fleets with multi-site operations may run hybrid models. Key decision factors: technician availability and wages in your market, parts availability and pricing through OEM versus independent suppliers, geographic concentration of trucks (centralized vs distributed), and management capacity to run a shop operation. In-house typically reduces direct cost 15-30% and provides faster turnaround on routine service, but requires capital investment in shop, tools, and inventory. Most successful fleets use software platforms to track PM regardless of in-house vs outsourced — the scheduling, documentation, and trend analysis discipline matters more than the venue. Talk to our sales team for help structuring your PM operation.