By Norman Ford · Updated October 2026
Truck maintenance: PM service levels, schedules and records
A truck that gets its service on time breaks down less, lasts longer and is worth more when you sell it. That is the whole case for preventive maintenance. The hard part is not knowing what to do; it is doing it on time when loads keep coming. This guide explains how PM programs are usually built, what the federal rules require, and how to fit service around the work.
The PM service levels
Most shops and fleets group preventive maintenance into levels. The names and contents vary, so treat this as a typical pattern and ask your shop what its levels include. Every interval comes from your OEM spec.
Tap a numbered balloon for the part's job, check and spec.
| ITEM | PART | WHAT IT DOES | CHECK |
|---|---|---|---|
| 1 | Daily: pre-trip and post-trip | Driver inspection of tires, lights, brakes, air system, steering, coupling, fluids and leaks, with defects written up. | Use a checklist; repair defects before the truck runs. |
| 2 | PM A: frequent service | Usually engine oil and filter, chassis lube, fifth wheel grease and a safety inspection of brakes, tires, steering, lights and the air system. | |
| 3 | PM B: extended service | Usually adds fuel filters, air filter checks, coolant tests, more detailed brake and suspension inspection and fluid sampling. | |
| 4 | PM C: major service | Usually adds longer-interval items: coolant service, transmission and axle fluids, valve adjustment, aftertreatment service and component inspections. |
Why intervals vary so much
Two trucks of the same model can have very different schedules. Engine makers set intervals by oil type, fuel economy, duty cycle and idle time, and many publish separate schedules for severe service: heavy loads, frequent idling, short trips, dusty or hot conditions. A box truck doing local stop-and-go work may need service sooner by miles than a highway tractor. Many makers count engine hours too, and whichever limit comes first applies.
That is why this guide does not give one number for an oil change. The right number is in your owner's manual.
The federal maintenance rule
Commercial motor vehicles fall under the federal systematic maintenance rule. Under 49 CFR 396.3, every motor carrier must systematically inspect, repair and maintain all vehicles under its control, and keep parts and accessories in safe and proper operating condition at all times.
Source: 49 CFR 396.3, checked October 2026
For each vehicle controlled for 30 consecutive days or more, the carrier must keep records that identify the vehicle, show a schedule of inspection and maintenance, and record inspections, repairs and maintenance with the date and nature of the work. Separate rules cover the annual periodic inspection (49 CFR 396.17) and driver vehicle inspection reports (49 CFR 396.11). Maintenance records come up in safety audits, so keep them complete.
Building a truck maintenance plan
- Collect the intervals. From the OEM manuals for the engine, transmission, axles and body equipment, by miles, hours and months.
- Group them into levels. Items with similar intervals go together, so the truck visits the shop fewer times.
- Turn intervals into dates. Use your real weekly miles. The preventive maintenance schedule generator does the math and prints the result.
- Pick the shop. Choose where each level is done, near home or on a lane you run often.
- Book ahead. Treat each service like a delivery appointment.
- Record everything. Date, mileage, work done, parts and cost, in a truck maintenance log.
For what each visit should cover in detail, use our truck maintenance checklist.
Diesel truck maintenance items that are easy to miss
- Aftertreatment. The DPF, SCR system and DEF filter have their own service intervals.
- Cooling system. Coolant degrades; test it, do not just top it up.
- Air dryer cartridge. Moisture in the air system causes valve and brake problems.
- Wheel seals and hub oil. Small leaks become wheel end failures.
- Body equipment. Reefer units, liftgates, hydraulic pumps and PTOs have their own schedules.
- Fifth wheel. Grease and adjustment, plus a check of the locking jaws.
The annual inspection and PM together
Every commercial vehicle must pass a periodic inspection at least once every 12 months under 49 CFR 396.17, with the inspection report or a record kept. Many owners schedule the annual inspection together with a PM B or C service, so the truck is only in the shop once and any defects found during the inspection can be fixed on the spot. Book it a month ahead of the due date, so a failed item does not leave the truck without a current inspection.
Mobile PM service
Mobile PM services bring the technician to your yard or parking spot for routine work such as oil changes, lube, filters and inspections. For a small fleet that parks in one place, mobile service can save hours of driving to and waiting at a shop. It works best for routine items; larger jobs still need a shop with a lift and parts on hand. Ask what is included, how records are provided, and whether the service handles used oil and filter disposal.
Truck fleet maintenance
With more than one truck, the challenge is keeping service from piling up on the same week. Stagger the schedules, track each truck separately, and keep one record system for the whole fleet. Fleet maintenance programs from shops and dealers can handle scheduling for you; compare what is included, and keep your own records either way.
When the plan meets the road
PM schedules fail in a predictable way: the service comes due in the middle of a busy week, and it gets pushed back one more load, then another. The fix is to plan the loads around the service instead of the other way around. That is where dispatch and maintenance meet.
Maintenance protects against big repair bills
Most large repairs start as small problems: a weeping seal, a cracked hose, a worn belt, a slack adjuster drifting out of adjustment. PM inspections catch them early, when they are cheap. When a repair is needed, our guide to semi truck repair covers choosing a shop and getting a straight diagnosis.
Some owners also buy an extended warranty to cap the cost of a major failure on an older truck. Our guide to semi truck warranty explains how those plans work.
Budget for maintenance per mile
Maintenance is a cost of every mile, even when the bill comes months later. Setting aside a reserve per mile, and including it in your rate, keeps a large service from becoming a cash crisis. Our guide to semi truck maintenance cost covers typical costs, and the maintenance reserve calculator helps set the number.
Where we fit
We are a dispatch desk for 26 ft box trucks and larger, not a shop. We ask for your service schedule when you start and plan loads around it. Learn more about our dispatch service.