Keeping Class 7–8 Trucks on the Road: Common Repairs & How to Avoid Costly Downtime

Class 7 and 8 trucks are the lifeline of freight movement across the U.S. But keeping them on the road and out of the shop takes more than just routine oil changes. With breakdowns costing an average of $448–$760 per day in lost revenue, preventive maintenance and early issue detection are non-negotiable.

At Kooner Fleet Management Solutions, we work with fleet operators nationwide to reduce downtime, extend asset life, and keep revenue rolling.

Breakdown of the most common repairs we see on Class 7–8 trucks, and how to avoid them:

1. Brake System Repairs

Common issue: Air leaks, worn-out brake shoes, or ABS malfunctions

Risk: Safety violations, CSA score penalties, delayed deliveries

Solution:

• Perform regular inspections of air lines and compressor output

• Use brake stroke indicators to spot issues before they become violations

• Implement brake monitoring alerts through your fleet telematics system

At Kooner, we help fleets install predictive diagnostic tools that flag brake issues before they lead to roadside failures.

2. Engine Overheating & Failure

Common issue: Coolant leaks, clogged radiators, faulty sensors

Risk: Engine seizure, towing, and replacement costs

Solution:

• Stick to OEM-recommended coolant flush schedules

• Inspect sensors and thermostats monthly

• Use real-time engine temperature monitoring

Kooner’s preventive maintenance programs catch overheating risks before they lead to catastrophic engine damage, saving tens of thousands in rebuild costs.

3. Transmission Troubles

Common issue: Fluid leaks, delayed shifting, gear slipping

Risk: Transmission rebuilds averaging $4,000–$8,000

Solution:

• Conduct fluid analysis during routine inspections

• Watch for driver-reported issues like delayed gear engagement

• Keep software and firmware updated in automated manual transmissions (AMTs)

Our team tracks transmission health via connected diagnostics, so issues are addressed early, not after the tow truck is on the way.

4. Electrical Failures

Common issues: Faulty wiring, battery drain, and alternator issues

Risk: Unplanned downtime, safety hazards, inspection failures

Solution:

• Train drivers to identify dashboard warning signs

• Test battery and charging systems every 90 days

• Use electrical system scan tools to detect hidden faults

Kooner technicians perform regular multi-point inspections and help fleets install smart diagnostic systems that keep Class 8 electricals in check.

5. DEF System Problems

Common issue: Crystallization in lines, sensor failures, clogged filters

Risk: Derating, out-of-service orders, expensive SCR repairs

Solution:

• Keep DEF tanks sealed and away from contaminants

• Educate drivers on proper DEF handling

• Invest in DEF system health monitoring tools

We’ve helped fleets reduce DEF-related downtime by over 40% by implementing early detection tools and driver DEF training programs.

How to Reduce Class 7–8 Downtime With a Fleet Partner You Trust

Avoiding costly truck repairs isn’t about luck — it’s about systems. At Kooner Fleet Management Solutions, we offer:

1. Telematics-based diagnostics

2. Predictive maintenance planning

3. Service scheduling based on real vehicle data

4. Custom maintenance calendars for your fleet size and usage

We understand that every hour your truck is off the road is money lost, and our goal is to maximize uptime, reduce repair costs, and extend your asset life.

Get Proactive with Fleet Maintenance — Partner with Kooner

Whether you run 10 trucks or 500, our experts can tailor a fleet maintenance strategy that keeps your Class 7–8 assets moving and your bottom line protected.

Talk to Kooner Fleet Management Solutions today to set up a preventive maintenance strategy that works.

Don't wait for a roadside emergency. Get ahead of repairs — and stay ahead of the competition.