A mileage-based fleet preventive maintenance schedule for commercial trucks: daily, weekly, and PM-A, PM-B, and PM-C service intervals so you know exactly what to do at every odometer mark.
By Vladimir Sardari · Owner & Lead Technician 
Fleet preventive maintenance is best organized by mileage, not guesswork. Most commercial fleets run a tiered schedule: daily and weekly driver checks plus three escalating service levels keyed to the odometer. PM-A is a light service usually performed every 10,000 to 25,000 miles (lube, oil, filter, and a safety inspection), PM-B adds drivetrain and brake work at roughly twice that interval, and PM-C is a comprehensive annual or high-mileage overhaul of major systems. Building your program around these intervals turns maintenance from a reactive scramble into a predictable, mileage-triggered routine.
This guide breaks down what belongs at each mileage tier so dispatchers, fleet managers, and owner-operators can assign the right work to the right odometer reading. Always confirm exact intervals against your specific engine and chassis OEM service manual, since duty cycle, engine make, and operating conditions all shift the numbers.
A flat "inspect everything" checklist treats a truck at 8,000 miles the same as one at 240,000 miles. That wastes labor on new equipment and under-serves high-mileage units. Mileage tiering solves this by matching the depth of service to wear that actually accumulates with distance.
The U.S. Department of Transportation, through the Federal Motor Carrier Safety Administration (FMCSA), requires every motor carrier to systematically inspect, repair, and maintain its commercial vehicles and to keep maintenance records under49 CFR Part 396. A mileage-keyed PM program is the cleanest way to prove that systematic process during a DOT audit because each service ties to a documented odometer trigger.
A few factors will compress your intervals:
The foundation of any fleet PM program is the daily driver inspection, which happens regardless of mileage. FMCSA regulations require a driver to be satisfied the vehicle is in safe operating condition before driving and to complete a driver-vehicle inspection report (DVIR) when a defect is found. Daily checks catch the fast-developing problems mileage intervals can miss:
Any defect that affects safe operation should pull the truck from service until repaired. This is also where small fixes like a burned-out marker lamp or a glad-hand seal get caught before they become a roadside violation.
Between formal PM services, a quick weekly walkaround catches slow leaks and creeping wear:
PM-A is the most frequent scheduled service and the workhorse of the program. It centers on lubrication, oil, and a structured safety inspection. Many fleets align PM-A with their oil change interval, which is why the mileage range is so wide — confirm the drain interval with your engine OEM and oil supplier rather than defaulting to an old number.
A typical PM-A includes:
This is also the natural point to scan for active and pending diagnostic trouble codes so an emissions or sensor issue gets flagged before it escalates into a derate.
PM-B includes everything in PM-A and layers on deeper drivetrain, brake, and chassis attention. At this interval, components that wear gradually over tens of thousands of miles get measured and serviced:
Because PM-B touches the brake system in depth, it pairs well with a formal DOT brake inspection so the truck stays inspection-ready and the work is documented together. Catching an out-of-adjustment slack adjuster or a thinning lining here is far cheaper than a roadside out-of-service order.
PM-C is the comprehensive overhaul-level service, usually performed annually or at high-mileage milestones. It folds in PM-A and PM-B items plus the major-system work that only comes due infrequently:
PM-C is also a logical time to align with the annual DOT periodic inspection required under FMCSA rules, so the truck's compliance clock and its heaviest service reset together.
A mileage schedule only works if something fires the alert. Whether you use fleet software, a spreadsheet, or telematics odometer feeds, set a trigger window before each PM mile mark so the truck can be scheduled without taking it off a load unexpectedly. Record the odometer, date, parts, and findings for every service — those records are exactly what FMCSA Part 396 expects you to retain.
When a unit is hundreds of miles from the shop, mobile service keeps the schedule intact. On-site fleet repair brings PM-A and PM-B service to your yard or a roadside location so a single overdue truck doesn't drag down your whole compliance program, and emergency roadside truck repair handles the breakdowns that slip through between intervals.
PM budgeting depends on more than the service tier. Costs scale with truck class and engine, the price of oil and filters at the volume your fleet buys, labor time for the inspection depth involved, and how many deferred items surface during a higher-tier service. Fleets that hold tight to PM-A intervals generally see fewer expensive PM-C surprises, because small problems get caught while they are still adjustments rather than replacements.
PM-A is a light, frequent service focused on lube, oil, filter, and a safety inspection. PM-B adds deeper brake, drivetrain, and chassis work at a longer interval. PM-C is the comprehensive, often annual service that covers major systems like cooling, emissions, and wheel ends. Each higher tier includes the work from the tiers below it.
It varies by duty cycle and OEM specification. A common structure is daily driver inspections, weekly walkarounds, a PM-A light service every 10,000 to 25,000 miles, PM-B every 25,000 to 50,000 miles, and PM-C annually or at high-mileage milestones. Always confirm exact intervals with your engine and chassis manufacturer.
The Federal Motor Carrier Safety Administration requires carriers to systematically inspect, repair, and maintain their commercial vehicles and to keep maintenance records under 49 CFR Part 396. It does not dictate specific mileage numbers, so a mileage-keyed PM program is one of the cleanest ways to demonstrate that systematic process.
Use both when idling is heavy. Mileage drives most chassis and drivetrain wear, but engine hours capture wear from idling that the odometer never records. High-idle units, such as those running an APU or sleeping in cab, benefit from engine-hour triggers alongside mileage.
Yes. Most PM-A and PM-B service items, including oil changes, lubrication, brake inspections, and filter changes, can be performed on-site at your yard or terminal with mobile service, which keeps trucks on schedule without long shop downtime.
Need to keep your fleet's PM schedule on track? 916 Truck Repair provides mobile, on-site preventive maintenance and repair across the Sacramento metro and Northern California. Call (916) 898-9090 for 24/7 mobile dispatch.
Mobile truck repair for highway breakdowns, truck stops, fleet yards, docks, and roadside service calls.
Call (916) 898-9090