Detroit DD8
7.70L Inline-6 turbo diesel • Detroit Diesel
About the Detroit DD8
The Detroit DD8 is Detroit Diesel's 7.7L medium-duty engine — Detroit's first medium-duty offering since exiting the Series 50 segment. Launched 2018 to give Freightliner M2 buyers a Detroit-branded engine alternative to Cummins B6.7. Same chassis can spec DD8 or Cummins B6.7 — DD8 became Daimler's preferred option for fleet-owned Freightliner M2 medium-duty trucks. Direct competitor to Cummins B6.7 in Class 6-7 medium-duty market.
Overview
The Detroit DD8 is Detroit Diesel's 7.7L medium-duty engine — Detroit's first medium-duty offering since exiting the Series 50 segment. Launched 2018 to give Freightliner M2 buyers a Detroit-branded engine alternative to Cummins B6.7. Same chassis can spec DD8 or Cummins B6.7 — DD8 became Daimler's preferred option for fleet-owned Freightliner M2 medium-duty trucks. Direct competitor to Cummins B6.7 in Class 6-7 medium-duty market.
Specifications
- Manufacturer
- Detroit Diesel
- Displacement
- 7.70 liters
- Configuration
- Inline-6 turbo diesel
- Fuel type
- Diesel
- Horsepower
- 240–350 hp
- Torque
- 660–1050 lb-ft
- Production years
- 2018–present
- Truck classes
- Class 6-7
- Applications
- Medium-duty truck, vocational, school bus
Design and engineering
7.7L inline-6, parent-bore block, common rail injection, EPA 2017-compliant SCR + DEF aftertreatment. Engineered by Daimler Trucks (jointly with Mercedes-Benz Trucks Europe — same architecture as MB OM936).
Generations and emissions eras
Reliability and longevity
Too new for long-term data. Daimler's track record suggests it will age well — particularly if Daimler stays committed to the segment.
Common problems
DEF/SCR issues consistent with industry. Limited dealer-tech familiarity vs Cummins B6.7.
Pros and cons
✓ Pros
- • Detroit engine in medium-duty
- • Daimler dealer support
- • Solid Mercedes-Benz engineering heritage
⚠ Cons
- • Newer engine — limited long-term data
- • Smaller third-party rebuild network vs Cummins B6.7