Our commitment to excellence and innovation sets us apart as we cater to a diverse clientele, ranging from individual truck enthusiasts to large fleet operators. Our expert team specializes in transforming standard trucks into exceptional machines that meet and exceed your specific needs.

Understanding Truck Modification
Truck modification involves customizing and upgrading various truck components to enhance its performance, appearance, or functionality. This process can range from simple aesthetic changes to complex performance upgrades. Truck modifications are essential to truck ownership and fleet management, whether for improved efficiency, compliance with specific industry standards, or simply a personal touch.
Why Modify Your Truck?
Custom truck modifications can significantly enhance a truck's performance, safety, and aesthetics. They can also increase the vehicle's value and longevity, making it a worthwhile investment for individual owners and fleet operators. At Harmon Truck Service, we understand the importance of these modifications and are dedicated to delivering results that surpass expectations.
Our Range of Services
Engine and Performance Upgrades
Enhancing your truck's engine performance is vital for increased efficiency and power. Our services include turbocharging, ECU (Engine Control Unit) tuning, and exhaust system upgrades. These modifications can significantly improve horsepower, torque, and fuel efficiency.
- Turbocharging: Adding a turbocharger can increase the air entering the engine, thereby boosting power without significantly increasing fuel consumption.
- ECU Tuning: This involves reprogramming the Engine Control Unit to optimize engine performance, balancing power output with fuel efficiency.
- Exhaust System Upgrades: Upgrading the exhaust system can improve engine efficiency and power output by reducing back pressure and enhancing engine breathing.
Suspension and Brake Upgrades
A truck's suspension and brakes are critical for safety and comfort. We offer custom suspension setups and brake system upgrades tailored to your truck’s specific use, whether off-roading, heavy hauling or long-distance travel.
- Suspension Upgrades: These include lifting or lowering kits, shock absorbers, and air suspension systems, ensuring your truck handles well under various conditions.
- Brake System Upgrades: Upgrading to high-performance brake pads, rotors, and calipers enhances stopping power, a crucial factor for heavy-duty trucks.
Custom Interiors and Exteriors
Personalize your truck with custom interior and exterior modifications. From bespoke upholstery and infotainment systems to custom paint jobs and body kits, we ensure your truck stands out.
- Interior Customization: We offer custom seating, dashboard enhancements, and advanced audio and navigation systems for a comfortable, high-tech driving experience.
- Exterior Modifications: These include custom paint jobs, body kits, and lighting upgrades, giving your truck a unique and appealing look.
Areas We Serve
Harmon Truck Service proudly serves a wide region, including Cuba, MO; Clayton, MO; St. Peters, MO; Chesterfield, MO; Lebanon, MO; and Glenallen, MO. We are committed to providing top-notch services to our clients in these areas, ensuring their trucks are modified to perfection.
Expert Truck Modifications at Harmon
At Harmon Truck Service, we blend expertise, innovation, and attention to detail to provide the best truck modification services in Sullivan, MO, and its surrounding areas. Whether you want to enhance performance and safety or simply want a truck that reflects your style, we are here to make it happen. Contact us today to transform your truck into the machine of your dreams.

