Truck Preventive Maintenance Schedule: What to Service and When

Your truck doesn't warn you before a breakdown — it warns your bank account after one. A tow, a hotel, a missed delivery, and a broker relationship can all go sideways because an oil change got pushed a few thousand miles too long. A preventive maintenance schedule exists so you control when the truck is in the shop, not the other way around.

This is a working PM schedule for owner-operators running Class 8 diesel trucks. It covers the main service intervals, what's checked at each level, and the regulatory records you're required to keep. Always use your OEM service manual as the final authority — engine, transmission, and axle manufacturers publish specific intervals for their equipment, and those specs override general rules of thumb.

Why a Written PM Schedule Matters

A lot of experienced operators keep their maintenance "in their head." That works fine until you're running harder, hauling different freight, or simply distracted for a stretch. A written schedule with clear mileage and time triggers is something you can check against objectively.

It also matters for:

• CSA scores — Vehicle Maintenance is one of FMCSA's seven BASICs. Roadside violations for brakes, tires, and lights accumulate in your Safety Measurement System profile. A current PM program means fewer defects when an inspector opens the door.
• DOT annual inspection — Every commercial motor vehicle must pass an annual inspection per 49 CFR Part 396, Appendix G. Having documented service history shows the inspector you're managing the equipment.
• Resale value — A truck with clean service records sells for more than one with a folder of mystery invoices.

The Four Tiers of a PM Program

A practical PM program has four tiers: pre-trip, routine PM (oil-change level), intermediate PM (major fluids and system check), and annual. Here's what belongs at each level.

Pre-Trip (Every Day)

Pre-trip is a regulatory requirement under 49 CFR 392.7, not optional. It's also your earliest warning system for anything that went wrong overnight or on the last run.

Engine compartment:

• Engine oil level
• Coolant level and hose condition (look for cracks, soft spots, bulging)
• Power steering fluid
• Belt condition (fraying, glazing, tension)
• Any visible leaks on the ground under the truck

Lights and electrical:

• Headlights, taillights, brake lights, clearance lights, markers
• Turn signals (tractor and trailer)
• Hazard lights

Tires:

• Tread depth and condition (cuts, bulges, sidewall damage)
• Tire inflation — check with a gauge, not by thumping
• Valve stem caps

Brakes:

• Air system builds to operating pressure in under 3 minutes (general guideline — verify your system's spec)
• Slack adjusters and pushrod stroke (manual adjustment check before departure)
• Air leak-down rate within federal limits

Coupling and trailer:

• Fifth wheel latch engagement, safety latch secured
• Kingpin and apron condition
• All trailer electrical connections (ABS light, lights)
• Trailer tires, mud flaps, conspicuity tape

Document anything found and repaired. The driver vehicle inspection report (DVIR) is required whether defects were found or not.

Routine PM — Level A (Every 15,000–25,000 Miles or Per OEM)

This is your oil-change service level. Exact mileage depends on your engine, oil spec, and duty cycle — a long-haul highway operation may extend toward the higher end of that range using full-synthetic oil; a local/regional or severe-duty operation may shorten it. Check your engine manufacturer's recommendation.

Engine:

• Engine oil and filter change (record oil type, quantity, filter part number, and mileage)
• Fuel filter inspection — primary and secondary (replace if restricted or per interval)
• Check and top off all fluid levels: coolant, power steering, washer fluid
• Inspect all belts and hoses; replace anything showing wear

Tires:

• Record tread depth per tire (don't just look — use a gauge)
• Check and correct inflation (steer, drive, trailer)
• Inspect for irregular wear patterns (often indicates alignment, balance, or suspension issues)
• Rotate per your rotation schedule if applicable

Brakes:

• Check pushrod stroke on all service brake chambers (per 49 CFR 393.47)
• Inspect brake hoses and lines for wear, chafing, and leaks
• Check slack adjusters for free-stroke and automatic adjustment function

Lights and electrical:

• Replace any burned-out bulbs
• Inspect trailer connector pins for corrosion

Chassis:

• Lubricate fifth wheel (clean and re-grease if built up with old grease mixed with debris)
• Lube all grease fittings per OEM chart: kingpins, tie rod ends, steering gear, U-joints
• Inspect steering components for play or binding

Interior:

• Test all gauges and warning lights with ignition on
• Check seatbelt function

Intermediate PM — Level B (Every 50,000–100,000 Miles or Per OEM)

Level B is a deeper service performed every other Level A interval or on a separate mileage trigger, depending on the manufacturer. Think of it as Level A plus the fluid and system work that doesn't need changing every oil cycle.

All Level A tasks, plus:

Cooling system:

• Test coolant freeze protection (refractometer)
• Test SCA (supplemental coolant additive) concentration and add if needed
• Inspect radiator and charge air cooler for debris, bent fins, external leaks

Transmission:

• Check fluid level; inspect for contamination or metallic particles
• Change fluid per manufacturer interval (varies significantly between manual and AMT)
• Inspect input and output seals for leaks

Rear axles and differentials:

• Check gear oil level; inspect drain plug for metal contamination
• Change fluid per manufacturer interval
• Inspect axle seals and breather vents

Air system:

• Drain and inspect air dryer desiccant; replace if saturated or discolored
• Check air governor cut-in/cut-out pressure
• Drain all tanks and inspect for moisture or contamination

Exhaust and aftertreatment:

• Inspect exhaust system for leaks, cracks, or mounting issues
• Check DEF level and system for fault codes; inspect DEF tank and lines
• Note current DPF regeneration frequency (excessive regen cycles indicate an issue)

Suspension:

• Inspect leaf springs or air springs for cracks, broken leaves, or leaks
• Check torque rods and bushings for wear
• Inspect shock absorbers for leaking or damage

Frame and body:

• Inspect frame rails for cracks or damage (especially around cross-members and brackets)
• Check all body mounts and sleeper attachment points

Annual PM and DOT Inspection (Every 12 Months)

Federal regulations require an annual inspection for every CMV per 49 CFR Part 396, Appendix G. The annual inspection covers brakes, tires, steering, coupling devices, lights, suspension, and frame — in thorough detail.

Best practice: schedule a pre-inspection PM one month before the inspection expires. Find and fix issues on your timeline, not the inspector's. Carrying a defect into the inspection creates mandatory downtime you didn't plan for.

What to have ready for the annual:

• Current brake adjustment on all axles
• Tires meeting minimum tread depth (4/32" steer; 2/32" drive and trailer per 49 CFR 393.75)
• All lights functioning
• No air leaks exceeding allowable drop-rate
• Coupling device in good condition
• Current registration and insurance

Retention requirement: Keep the annual inspection report for 14 months.

PM Schedule Summary Table

The mileage intervals in this table are illustrative starting points. Your engine, transmission, and axle manufacturers publish their own intervals — use those.

Records You're Required to Keep

Per 49 CFR Part 396, you must maintain maintenance records that identify:

• The vehicle (VIN or unit number)
• The work performed
• The date of the work
• Mileage at time of service (or next due mileage if interval-based)

Retention: minimum 1 year while the vehicle is in your fleet, and 6 months after it leaves. Keep the vendor invoices too — they show who did the work, what parts were used, and what was found.

The Difference Between Intervals and Reminders

Knowing the intervals is half the job. The other half is actually hitting them. Trucks get busy, you push a Level A 2,000 miles past due, then something comes up, and now you're at 5,000 miles overdue. The PM gets harder to catch up to the busier you are — which is exactly when you're most vulnerable to a breakdown.

Fleet management software that tracks each vehicle's service history and sends alerts before intervals come due removes the "I meant to do it" problem. You set the intervals once based on your OEM specs, and the system tracks mileage against them.

Connecting your PM records to expense tracking also gives you maintenance cost per mile by truck — a number that tells you which equipment is working and when an older rig's economics are turning negative.

And compliance tracking handles the document side: annual inspection expiration, registration, permits — so nothing regulatory falls through the cracks.

Truck Command keeps maintenance schedules per truck, sends reminders before services come due, and links every shop invoice to your expense records automatically. Plans start at $20/month with a 14-day free trial — no credit card required.

The PM schedule is only as good as the system behind it. Build the schedule, set the intervals, and let the reminders do the rest.