Thomas Built Buses Debuts First Saf-T-Liner HDX School Bus Equipped with Detroit DD8 Engine

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HIGH POINT, N.C. – (June 22, 2018) – Thomas Built Buses, along with Detroit, will feature the first Saf-T-Liner® HDX school bus equipped with the new Detroit™ DD8™ engine at the STN Expo in Reno, Nevada on July 17.  A 7.7L in-line 6-cylinder medium-duty engine with specific development for the Thomas Built Buses Saf-T-Liner HDX, the DD8 boasts a horsepower range of 260-350HP and a torque range of 660-860 lb.-ft.

The DD8 engine, which is the latest in engine technology, will deliver proven power, performance and best-in-class fuel economy and reliability, in addition to easier serviceability and a low total cost of ownership. It features top-load oil and fuel filters and the longest service intervals in its class, with up to 45,000-mile change intervals. Plus, the oil and fuel filters are positioned above the frame rails for easier, faster and cleaner filter changes.

Manufactured from the ground up, the engine features a simple fixed-geometry turbo design that provides performance and reliability along with an integrated engine brake option for superior braking horsepower to extend service brake life. Plus, smart, fuel-efficient design makes the most of every gallon as the advanced common rail fuel system optimizes each injection event to minimize fuel consumption. The result is at least a three percent increase in fuel efficiency compared to other diesel engines in this category.

The DD8, which was specifically designed to produce low emissions, meets 2017 greenhouse gas (GHG17) standards and will continue to meet emissions requirements through 2020. In addition, the DD8 utilizes innovative technology such as variable cam exhaust phasing, which allows additional heat to the exhaust stream. This innovative technology enables efficient operation of the aftertreatment system in school buses in low speed stop-and-go operations.

“We are so excited to debut this new engine in our Saf-T-Liner HDX,” said Caley Edgerly, president and CEO of Thomas Built Buses. “There is nothing like this engine in the market today, and we cannot wait for our customers to experience how clean, fuel efficient and easy to maintain this engine is. Our partners at Detroit have truly engineered the best engine for the industry today.”

The DD8 also comes with, Detroit Connect Virtual Technician? remote diagnostic service. Virtual Technician provides in-depth and advanced engine diagnostic information. Within minutes, the driver or fleet manager knows the cause and severity of the code, and is provided with recommendations for fault resolution and if necessary, the parts needed to fix the problem. Critical faults are sent the Detroit Customer Support Center, where an expert analyzes the fault event and provides additional details to the fleet. Full fault event details, including fault event diagnostics, history and trends are available via the new Detroit Connect portal.

The Detroit DD5™ and the Detroit DD8 will be available for order in 2018 from any Thomas Built Buses dealer. 

For more information, contact a local Thomas Built Buses dealer.


About Thomas Built Buses

Founded in 1916, Thomas Built Buses is a leading manufacturer of school buses in North America. Since the first Thomas Built bus rolled off the assembly line, the company has been committed to delivering the smartest and most innovative buses in North America. Learn more at or at 

Thomas Built Buses, Inc., headquartered in High Point, N.C., is a subsidiary of Daimler Trucks North America LLC, the largest heavy-duty truck manufacturer in North America and a leading manufacturer of class 4-8 vehicles. Daimler Trucks North America produces and markets commercial vehicles under the Freightliner, Western Star and Thomas Built Buses nameplates. Daimler Trucks North America is a Daimler company.

About Detroit

Detroit offers a complete line of heavy-duty and medium-duty diesel engines, axles, transmissions, safety systems and connected vehicle services for the commercial transportation industry in both the on-highway and vocational markets. Detroit™ products are sold and serviced through a network of hundreds of locations throughout North America. Detroit™ is a brand of Detroit Diesel Corporation, a subsidiary of Daimler Trucks North America LLC.



The Detroit DD8 engine now powers Thomas Built Buses Saf-T-Liner HDX model
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