How do I set up a preventive maintenance schedule?

Chapter 01

What does the law say my maintenance schedule must include?

The federal maintenance rule gives no intervals and no form. It says you must inspect, repair and maintain every truck and trailer you control, and do it “systematically”, which means by a plan. For each vehicle you have for 30 days in a row, your records must show three things. They show which vehicle it is, what inspection and service is due and when, and what was done and when (the maintenance rule). Two more records sit beside it: the annual inspection and the driver’s defect reports.

Here is how that looks in real life. Say you run four trucks under your own USDOT number, each with its own trailer. You have no shop of your own. Three trucks run long haul across the country. The fourth is a day cab. It runs short loads around the city and waits for hours at the docks with the engine idling.

On September 3, 2026, an officer at a weigh station inspects truck 3. The annual inspection decal on the truck is dated August 2025, so the inspection is more than 12 months old. The rule says you must not use a truck unless it passed that inspection in the last 12 months. The proof must be on the truck (the annual inspection rule). The officer writes it up as a violation on the inspection report.

That report is now your job. The driver must hand you a copy at the next terminal. If he will not get there within 24 hours, he must send it to you at once. Within 15 days of the inspection, you sign the report to certify that every problem on it is fixed. Then you keep a copy for 12 months (the roadside inspection rule). One thing changed on July 22, 2026. You now send the signed form back only if the State that issued it asks for it. Before that date, every carrier had to return it (FMCSA’s June 2026 rule). So truck 3 goes to a shop the next morning, before it takes another load. It passes its annual inspection on September 4, and you sign the roadside report.

Then you ask the harder question. When were the other three trucks inspected, and the four trailers? When did each truck last get its oil changed? The answers are in a glovebox, an email from a shop and a driver’s memory. Without a schedule, you are relying on luck to catch the next service date.

So you read what the rule asks for. It wants “a means to indicate the nature and due date of the various inspection and maintenance operations to be performed” (the maintenance rule). In plain words, you need a list of what service each vehicle needs and when it is due. That list is your preventive maintenance schedule. The rule does not say how to keep it. It names no form, so a notebook, a spreadsheet or an app can do the job. Some owners call it a vehicle maintenance log. The name does not matter. The due dates do.

The same record must say which vehicle it is. That means your unit number if the truck carries one, the make, the serial number, which is the VIN, and the year. If you do not own the vehicle, the record names the person who supplies it, such as an owner-operator leased to you. One detail changed on July 21, 2026. The rule used to ask for the tire size too, and FMCSA removed it as out of date (FMCSA’s July 2026 corrections). Older templates still have a box for it. You no longer need to fill it in.

The record must also show each inspection, repair and service, “indicating their date and nature” (the maintenance rule). A shop invoice that shows the date, the truck and the work done carries exactly those facts. Keep it all where the truck is based or maintained, for a year, and for 6 months after the truck leaves you. The rule has no exception for small fleets. It covers one truck the same way it covers ten.

Count your trailers too. In the federal rules, a “motor vehicle” includes a trailer (the definitions rule). So each of your four trailers needs its own file and its own annual inspection.

What must all this keep in good shape? The rule says parts and accessories must be “in safe and proper operating condition at all times”. It names the frame, the suspension, the axles, the wheels and rims and the steering, on top of the federal equipment rules (the maintenance rule). A separate rule says each vehicle must be properly greased and free of oil and grease leaks (the lubrication rule).

Why does the file matter so much? A new company gets a safety audit, and the auditor asks for maintenance records for every truck and trailer. Our list of audit documents shows the whole set. Three of the 16 problems that fail that audit outright sit in this part of the rules. Running a truck that an officer put out of service before it is fixed fails it. So does letting a truck run before you fix a defect on your driver’s report that is bad enough to put it out of service. Missing annual inspections fail it when they show up on 51% or more of the records examined (the audit failure rule). What automatically fails the audit explains each one. Brakes, tires, lights: what puts a truck out of service explains which defects park a truck and what to do next. So the schedule is where you start. Next comes what goes on it.

Chapter 02

How do I choose the service intervals for each truck?

Take them from the makers’ guides. The engine maker sets the intervals for the engine, such as the oil and the filters. The truck maker covers the rest of the truck. The engine guide we look at below gives each service a mileage and a time limit, and for the hardest work an hour limit too. Put them all on the sheet and do the work at whichever comes first. The federal rule leaves the numbers to you, so the maker’s guide is the best source you have. A number from a forum or from a friend’s truck is not.

To see what a maker’s guide looks like, take one real example. Cummins publishes a short quick reference guide for its 2021 X15 engine (Cummins’ guide). It sorts trucks into duty cycles by fuel economy, in miles per gallon, or mpg. Severe duty is from 3 to 4.9 mpg. Short haul is from 5 to 5.9. Normal is from 6 to 6.9, and light is 7 and up. On that guide, the oil change interval is 25,000 miles in severe duty, 50,000 in short haul, 60,000 in normal and 75,000 in light duty. Each one also has a limit of 12 months. The fuel filters follow the same miles.

That guide is for one engine only. Another engine, or another year of the same engine, can have other numbers. So find the guide for the engines in your trucks, and use it the same way. Notice, too, what the engine guide leaves out. For the coolant, it says “Follow OEM coolant recommendations”, which sends you to the truck maker’s manual. You need both guides for each truck.

Now work out each truck’s duty cycle. You need two numbers from your own records: miles driven and gallons bought. Divide the miles by the gallons. Say truck 1 drove 31,500 miles last quarter and bought 5,000 gallons. That is 6.3 miles per gallon, so on this guide it is in normal duty. Trucks 2 and 3 come out about the same. Their oil comes due every 60,000 miles. At about 126,000 miles a year, that is roughly every six months. Truck 4 comes out very differently, and the next section is about it.

The oil is only the first line on each sheet. The same guide lists jobs that come up rarely. The overhead adjustment, which sets the engine’s valves, comes every 500,000 miles, 10,000 hours or 60 months (Cummins’ guide). Jobs like that are the ones nobody remembers. They belong on the sheet most of all.

For the rest of the truck, start from the list the annual inspection uses. It covers the brakes, coupling devices such as the fifth wheel, the exhaust and fuel systems, and the lights. It also covers safe loading, steering, suspension, the frame, tires, wheels and rims, the windshield and wipers, and a trailer’s rear impact guard. A vehicle fails the annual inspection with any defect on that list (the minimum inspection standards). So ask your shop to check those items at every PM service, not once a year. Add greasing, since the rules want every vehicle properly greased. That helps you avoid surprises at the DOT annual inspection.

You will also hear about oil analysis. A lab tests a small sample of used oil and reports what is in it. It is a tool you can ask your shop about. But do not stretch an oil change interval on your own because of it, or because you switched oils. The Cummins guide allows longer intervals only in the cases it spells out on the page, such as a Cummins program it names. It also warns, in capital letters: “DO NOT EXTEND oil drain intervals with synthetic or semi-synthetic oils” (Cummins’ guide). If you want a longer interval, ask the engine dealer what the maker’s own program requires. That covers the long-haul trucks. Truck 4 does not fit their schedule at all.

Chapter 03

What if one truck works harder than the others?

Give it its own schedule with shorter service intervals. Idling burns fuel without adding miles, and stop-and-go driving burns more fuel for each mile. So a truck in that kind of work gets fewer miles per gallon. On a guide like the Cummins one, that puts it in a harder duty cycle with shorter intervals. An idling engine also adds hours, not miles. So for a truck like that, watch the hour meter as well as the odometer. And check its duty cycle again whenever its work changes.

Here is truck 4, your day cab. Last quarter it drove 11,000 miles on 2,500 gallons. That is 4.4 miles per gallon, which puts it in severe duty on the Cummins guide. There, its oil comes due every 25,000 miles (Cummins’ guide). At about 44,000 miles a year, that is roughly every seven months.

Now see what happens if you put it on the long haul schedule by mistake. It would need 60,000 miles to reach the normal interval, and it will never get there in a year. So the 12-month limit would come first, and its oil would be changed once a year. That is five months later each time than its own guide allows. Nothing on your desk would look wrong. The truck would simply run on old oil.

The guide goes further for the hardest work. Below 3 mpg, it drops the oil change to 4,500 miles, 500 hours or 12 months, “whichever occurs first” (Cummins’ guide). Truck 4 is not that bad. But the line shows why hours matter. An engine idling at a dock for two hours a day runs up hours without a mile on the odometer. So on truck 4’s sheet, write down the engine hours at each service, next to the miles.

Your own guide may also list other conditions it treats as hard work. Read that page for each engine and each truck, and see which of your trucks fit. A truck’s work can change, too. If truck 1 moves to regional runs next spring, its mpg will tell you. Work out each truck’s mpg again every quarter from the same fuel records. When the number crosses a line, move the truck to a new schedule.

The time limit also protects the other end. Say you also kept an older truck as a spare, and it drove only a few thousand miles a year. It would never reach its mileage limit. But the 12-month limit on the guide would still apply. And before it went back on the road, its annual inspection would have to be less than 12 months old (the annual inspection rule).

You now have four sheets with the right numbers on them. Three follow the normal schedule, and one follows the severe schedule. A sheet does nothing on its own, though. Someone has to act on each line.

Chapter 04

Who does what when I have no shop of my own?

Split the job four ways. Your driver checks the truck before each trip and reports defects. You or your office keep the calendar and the files, and approve the work. An outside shop does the work. A qualified inspector does the annual inspection. But the rule keeps the whole job on you. You must maintain your vehicles, or “cause” them to be maintained (the maintenance rule). Handing a truck to a shop does not hand over that duty.

Start with the driver, because he sees the truck every day. Before driving, he must be satisfied that the truck is safe. If the last driver wrote a defect report, he reviews it and signs it. His signature says he saw that the repairs were certified (the driver inspection rule). Most people call this check the pre-trip.

At the end of each day, the driver writes a report on each truck he drove. He does this if he found a defect, or if someone told him of one. It is called a driver vehicle inspection report, or DVIR. It must cover at least 11 items. They are the service brakes and trailer brake connections, the parking brake, steering, lights and reflectors, and tires. They also include the horn, wipers, mirrors, coupling devices, wheels and rims, and emergency equipment. If he finds no defect, no report is needed (the DVIR rule).

Then it comes back to you. Before the truck runs again, you must fix any defect on the report that is likely to affect safety. Then you certify on the report that it was fixed, or that no fix was needed. You keep the report and your certification for 3 months. The rule does not apply to a carrier that runs only one truck (the DVIR rule). Since March 23, 2026, it also says plainly that the report can be electronic. FMCSA said this was already allowed, and the new wording only makes it clear (FMCSA’s February 2026 rule).

Those reports are also the best early warning your schedule has. A driver who writes “air leak, left rear” twice in a month is telling you something the calendar does not know. Keep every one in the truck’s file, even after the 3 months are up if you like. They are part of its history.

Next comes you, or whoever runs your office. This is the job that gets dropped when you are out driving yourself. Keep one folder or file for each truck and each trailer. Put in it the schedule sheet, every shop invoice, the latest annual inspection report, and the signed driver and roadside reports. Once a week, get each truck’s current miles and compare them with the next due items. You also decide which repairs to approve, so the shop knows who says yes.

The outside shop does the work. Its invoice becomes your record, so ask that every invoice show the unit number or VIN, the date, the miles and the work done. How to read a repair invoice line by line, and what to question, is in checking a truck repair estimate and invoice.

Brakes have a rule of their own. Anyone you employ who is responsible for brake work or brake inspections must be qualified. That takes approved training or a certificate, or at least one year of brake training or experience. For brake inspections, passing the CDL air brake tests counts. You keep proof of it at your main office (the brake inspector rule). If you or your drivers ever work on brakes yourselves, that rule is about you.

The annual inspection has its own rules about who may do it. You may do it yourself only if you meet the inspector qualifications. Or a commercial garage, a fleet leasing company, a truck stop or a similar business can do it for you. It must have the right facilities and qualified inspectors (the annual inspection rule). A qualified inspector understands the equipment rules and the inspection standards and can spot a bad part. He has passed a Federal or State training program, or holds a State certificate, or has at least 1 year of training or experience. Who can do my truck’s annual DOT inspection walks through choosing the inspector and checking the report.

Here is the trap. Even when a shop does the inspection, you must keep proof of its inspector’s qualifications. You keep it for as long as he inspects for you, and for one year after. The only exception is an inspection done under a State inspection program (the inspector qualifications rule). So ask the shop for a copy along with the report. If your State runs its own truck inspection program, ask the State whether it counts. We did not check which States have one.

The inspector’s report names the inspector, your company, the date and the vehicle. It lists the parts checked and the results, and certifies the inspection. You keep it for 14 months where the truck is based or maintained (the inspection records rule). The proof on the truck can be the report itself or a decal. The decal shows the date and the name and address of where the report is kept. It also identifies the vehicle if the truck is not clearly marked, and it states that the vehicle passed (the annual inspection rule). If you buy a truck that someone else inspected, getting that last report when an officer asks is still your job. The rest of the paperwork for a new truck is in adding or selling a truck without breaking the paperwork chain. With the jobs handed out, the next question is when each truck goes to the shop.

Chapter 05

How do I fit shop visits around my loads?

Put every due item for every vehicle on one calendar, by miles and by date. Look a few weeks ahead, so you can book each visit around a load or the driver’s home time. Spread the trucks out, so two are not due in the same week. Do several jobs in one visit: the PM service, the annual inspection and any open repairs. And book the annual inspection before its 12 months run out, not on the last day (the annual inspection rule).

Go back to your four trucks. Since September 4, truck 3’s annual inspection is fresh. You dig the other dates out of the files. Trucks 1 and 2 were inspected on November 10, 2025, with their trailers. Truck 4 and its trailer were inspected on March 10, 2026.

Trucks 1 and 2 are both due by November 10, 2026. If both go to the shop the same week, two of your three long-haul trucks stop together. So you move truck 2 up. Nothing stops you from inspecting a truck early. The rule asks only that it passed within the last 12 months (the annual inspection rule). Truck 2 goes in during October, when its oil change is due anyway. From then on, its 12 months count from October.

Now truck 1. It is at 430,000 miles, and its next oil change is due at 450,000. It runs about 2,400 miles a week, so the oil comes due in about eight weeks, near the end of November. But its annual inspection is due by November 10. Two shop days, three weeks apart, make no sense. So you do both in the first week of November, on a day truck 1 is near home. The oil is changed a few thousand miles early. That costs a little oil and saves a second day off the road.

That example is the whole weekly routine. Every Monday, get each truck’s miles and update the next due dates. Anything due in the next few weeks gets a shop date that fits the load plan. Anything due soon after gets added to that same visit. Write the booked date on the sheet, so everyone can see it.

Keep both kinds of limits on the calendar. Miles move every week, but dates do not wait. The annual inspections, the 12-month limits on oil and the jobs every 60 months are all dates (Cummins’ guide). Put each one on the calendar a month early, with its real due date next to it.

A schedule never makes a truck wait for a repair it needs now. A truck must not run in a condition likely to cause a crash or a breakdown. If a defect shows up on the road, the truck may go only to the nearest place where it can be repaired safely. Even that is allowed only if it is safer than leaving the truck where it is (the unsafe operations rule). When that happens, move the calendar around the repair, not the other way round. Each repair also adds to the truck’s history, helping you adjust its schedule.

Chapter 06

How do I adjust the schedule from repair history?

Every few months, read each truck’s file from start to end. The repair records and driver reports the rules already make you keep are your data. When the same part keeps failing before its next check, move that check earlier for that truck. When different parts keep failing on the same truck, the schedule is no longer the question. And never stretch an interval past the maker’s limit on your own (Cummins’ guide).

In December 2026, you sit down with truck 4’s file. It had its rear brake shoes replaced in March and again in August. In November, its driver wrote about the brakes on two reports. The long-haul trucks had no brake work all year. The pattern is plain. Truck 4’s city work wears out brakes, and a brake check at each oil change comes too late. So you and the shop agree on a brake check halfway between oil changes as well. Here is what truck 4’s sheet looks like after that change.

Truck 4. Unit 4 · [make] · VIN [number] · 2019 · owned by us.

Due, by miles or date, whichever comes first. Oil and fuel filters: every 25,000 miles or 12 months (severe duty on the engine guide). Last done June 12, 2026, at 161,000 miles and [hours]. Next: 186,000 miles or June 12, 2027. Brake check: at every oil change and halfway between, so every 12,500 miles (added December 2026 after two brake jobs). Next: 186,000 miles. Chassis check and grease, using the annual inspection list: at every visit. Annual inspection, truck 4 and its trailer: last March 10, 2026. Next: by March 10, 2027. Book it in February.

Done. March 5, 2026, 149,000 miles: rear brake shoes, [shop], invoice [number]. June 12, 2026, 161,000 miles: oil and filters, chassis check, grease, [shop], invoice [number]. August 20, 2026, 168,400 miles: rear brake shoes again, [shop], invoice [number].

Notice what the sheet holds. It names the vehicle, it shows what is due and when, and it lists what was done and when. Those are the three things the rule asks for (the maintenance rule). The same sheet is also the story of the truck, and that story is what moved the brake check.

The records also tell you when to leave things alone. Trucks 1 to 3 went all year without a brake job, and their driver reports are clean. Their schedule stays as the maker set it. Do not stretch it because nothing broke. The maker’s interval is the limit, unless the maker’s own program says otherwise.

Truck 2 tells a different story. This year it needed a turbocharger, then an injector, then a radiator. None of those came from a missed service, so a tighter schedule would not have saved it. When different parts keep failing on the same truck, the question is whether it is still worth fixing. Repair, overhaul or replace the truck walks through that choice. And if the same repair fails again soon after, look at the invoice first. Ask the shop whether that job came with a warranty before you pay for it twice.

Some advice you will find online is now out of date. Three changes in 2026 touch this page. Since March 23, 2026, the DVIR rule says plainly that reports can be electronic (FMCSA’s February 2026 rule). Since July 21, 2026, the maintenance record no longer needs the tire size (FMCSA’s July 2026 corrections). And since July 22, 2026, you return a signed roadside report only if the State asks (FMCSA’s June 2026 rule). You still certify it within 15 days and keep a copy for 12 months. Older guides also tell you to fill in a DVIR every day for every truck. The rule asks for one only when a driver finds or hears of a defect.

There are things we could not check. We read one engine guide, from Cummins, and used it only as an example. We did not read your truck makers’ manuals, and your own guides decide your intervals. We could not open Cummins’ own page about the program it names for longer intervals, so ask the dealer. And we found no reliable figure for what a PM program saves, so we give none. The figures we found came from companies that sell software or services.

If you would rather hand the calendar, the shop bookings and each truck’s file to someone, we do that work: here is what it costs.