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Preventative Maintenance Checklist for Semi Trucks

30th Sep 2025
Preventative Maintenance Checklist for Semi Trucks

Every truck driver knows one thing: semi-truck repairs are a nightmare for the pocketbook.

Sticking to a solid, consistent maintenance schedule is the best way to prevent this from happening. But like any good habit, it’s something we tend to put off for tomorrow…until it’s too late!

Your truck is your income. Preventative maintenance is a business strategy. 

In this post, we’ll cover the need for a preventative maintenance checklist, and some of the common replacement parts you can buy online and ship directly to your specified address.

Why Preventative Maintenance Matters for Semi Trucks

Truck driver standing on open semi truck hood with exposed engine components

Preventative maintenance can save you a lot of time and money, all while extending the life cycle of your big rig.

Routine maintenance tasks help to improve your vehicle’s performance and safety. As an owner-operator who is managing costs, good PM can lower unexpected overhead costs.

  • Lower repair costs (compared to emergency repairs)
  • Better fuel efficiency
  • Longer lifespan
  • Fewer unexpected breakdowns.

Ignoring PM can cost you:

  • Costly transmission issues
  • Excessive wear
  • Roadside failures or hgher risk of accidents 
  • Potentially a shorter truck lifespan and reduced resale value 

Common Issues Prevented by Routine Maintenance Checks

  • Overheating (neglecting your cooling system) 
  • Brake failure (worn-out pads, air leaks) 
  • Tire blowouts (from poor pressure, uneven tread depth) 
  • Electrical shutdowns (loose connections) 
  • Costly aftertreatment screwups (not doing DPF/DEF maintenance) 

Essential Maintenance Checks and Frequency

Tires
Check Daily
Replace them as tread wears down and do a quick tire check before every trip.
Fluids
Check Daily
Double check fuel levels, coolant, oil, and washer fluid before hitting the road.
Brakes
Inspect Weekly
Hard stops cause fast wear—inspect pads, drums, and lines regularly before trips.
Engine
Every 15k–25k mi
Inspect radiator, belts, compressor, gearbox, alternator, hoses, and wiring before long hauls.
Electrical
Check Weekly
Stay compliant—inspect wiring, clean connections, and verify all lights and signals work.

Who Can Inspect Your Truck?

FMCSA: establishes preventative maintenance requirements for most commercial truck inspections.

CVSA: creates the inspection standards and processes that your truck must meet.

State Troopers: they can perform real-time inspections if/when they pull you over. 

FMCSA requires there be preventive maintenance done on commercial vehicles.

How to Start a Preventative Maintenance Plan

#1. Check out your truck.
  • How often it’s driven
  • Current mileage
  • Fuel system
  • Weather conditions it drives in
#2. Build a schedule.

This will help you keep track of when inspections are due; keep a log book (Excel sheet or Binder) with tasks, date, mileage, and next due columns.

#3. Tell your drivers.

Set clear expectations about PM duties. (Fleet managers only); to do PM at scale, use apps like KeepTruckin, Fleetio, SimpleTruckELD.

#4. Document maintenance routines.

Keep a running record of cost per mile (helps you budget), performance checks, service repairs, or changes (like adding new semi truck tires).

Daily Driver Inspections (Pre-Trip and Post-Trip)

Pre- and post-trip inspections help you identify and repair budding issues immediately before they become major, costly problems.

The average yearly cost of doing routine mechanical inspections might sound high ($15k average), but it's minimal compared to major diesel truck repair costs in most shops. 

The BEST Pre-Trip & Post-Trip Checklist:

  • Tire PSI pressure and minimum tread depth (4/32" on steer tires, 2/32" on other tires).
  • Brake lights, wiper blades, airline leaks, and loose connections.
  • Fluid levels: engine oil, brake fluid, power steering fluid, wiper fluid (TIP: keep spare fluids in your truck just in case you need to top off)
  • Suspension components for cracks or wear.
  • Walk-around visual check for any leaks and verify that there are no dead marker lights. 

Preventative Maintenance — Mileage Bands (Estimated)

Heads-up
Duty cycle changes service intervals. Linehaul (steady highway) can stretch intervals; stop/start, heavy loads, extreme temps, or dusty routes shorten them. Always confirm with the truck manufacturer’s recommendations.
10k–25k mi / 6 mo
Routine
Oil & Filter Change engine oil & oil filter.
  • Inspect air filter & fuel filter.
  • Quick brake/tire/electrical check.
100k–150k mi
System
Air Dryer Replace desiccant cartridge.
  • DEF system service checks.
  • Valve adjustment (per engine spec).
250k–400k mi
Aftertreatment
DPF Clean/bake DPF per duty cycle.
  • Inspect doser & DEF quality.
  • Check sensors, clamps, CAC leaks.
500k mi / 60 mo
Driveline
Transmission Replace transmission fluid & filters.
  • Inspect clutch/shift linkages.
  • Check differential fluids (per OEM).
750k mi
Cooling
Coolant Flush & replace coolant (OAT/NOAT per OEM).
  • Pressure-test system & cap.
  • Inspect hoses, water pump, fan clutch.
Intervals are guides: confirm with your truck manufacturer, engine family, and operating environment. Severe service (stop/start, heavy loads, extreme temps, dusty routes) = shorter intervals. Linehaul highway = longer intervals when oil analysis and diagnostics support it.

Weekly & Monthly Preventative Maintenance Tasks

Weekly:

  • Inspect hoses, belts, and filters.
  • Re-check your fluid levels.
  • Test lights, dash gauges, and your horn.

Monthly:

  • Tire rotation and lug nut inspection (rust or moisture buildup)
  • Brake system (brake pads, drums, hydraulic/air lines)
  • Alignment checks, shock absorbers, bushings, linkages, and suspension

Long-Term Preventative Maintenance Schedule (By Mileage/Timeframe)

Include manufacturers’ recommendations for common service intervals:

  • Oil change & oil filter replacement.
  • Cooling system flush and replace coolant.
  • Transmission service to avoid transmission issues.
  • Differential and axle fluid changes.
  • Air filter service interval.

Stress differences between truck manufacturer guidelines and actual duty cycles (long-haul vs. severe service).

Seasonal Preventive Maintenance for Commercial Vehicles

Winter checklist:

  • Inspect wiper blades, defrosters, check braking system for moisture/ice.
  • Monitor air pressure when warm air or cold conditions fluctuate.
  • Wash salt off undercarriage to prevent corrosion.

Summer checklist:

  • Service cooling system, flush or replace coolant.
  • Monitor tire pressure as heat raises psi.
  • Check air conditioning and electrical system.

The Most Important Maintenance Needs for Vehicle Performance

Focus on the major components that directly impact uptime:

  • ENGINE: engine oil, oil filter, air filter, fuel filter.
  • BRAKES: brake pads, brake fluid, brake drums.
  • STEERING: power steering fluid, joints, suspension components.
  • TIRES: check tread depth, uneven wear, balance and alignment.
  • ELECTRICAL: check brake lights, turn signals, wiring to your alternator (not cuts or abbrasions), battery bank corrosion level, clean terminals.

Preventive Maintenance for Fleet Owners vs. Owner Operators

Fleet managers: Use standardized schedules, compliance logs, telematics tracking. Fleets have a more complex logistical schedule to adhere to if they want to do comprehensive PM across all of their trucks. 

Owner operators: Tailor PM tasks to your truck’s maintenance schedule and routes. It's a lot easier to handle since you're in charge of one truck, essentially. 

Shop for Diesel Truck Parts at 4 State Trucks

Be prepared for preventative maintenance with our broad selection of mechanical parts for your engine, AC, exhaust, and transmission system. Get any component you need shipped to your preferred location quickly and easily when you shop at 4 State Trucks. Questons about a part? Give us a call!

30th Sep 2025

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