Skip to Main Content
<Back to 49X

Proven Powertrains

Powered By Proven Performance.

Detroit® has never been a brand to stop improving. Case in point, the new Detroit® DD13®. Along with the Detroit® DD15®, the two engines represent the latest achievements in industry-leading power and productivity. Engineered for greater reliability than ever before, they offer new vocational power ratings to meet the demands of any application. Whether you're working on construction sites, in quarries, in logging – or even over the road – there's a Detroit engine option that delivers you the proven power to get payloads moving quickly with longer maintenance intervals and greater uptime than ever before.


Detroit Dd13

  • Thermal Control Valve to greatly improve regen performance
  • New power ratings for greater application coverage
  • Available front and rear engine power take offs (FEPTO / REPTO)
  • Engineered to offer less complexity and more durability
  • New aftertreatment system that's smaller and lighter with greater performance
  • Longer maintenance intervals
  • Better compression ratios and piston design for improved fuel economy
  • Detroit Connect Virtual Technician® remote diagnostic system, helps maximize uptime

Detroit Dd15

  • New ball bearing turbocharger that reduces friction to improve performance and fuel efficiency
  • New aftertreatment system that's smaller and lighter with greater performance
  • Improved EGR design and reduced emission system complexity
  • Reduced idle RPM
  • Increased common parts across models
  • New piston design with increased compression and improved swirl combustion for greater fuel economy

Available Engines


The DD13 engine offers the best of the best in cutting-edge diesel engine technology and engineering. It's been significantly redesigned with vocational jobs in mind, with numerous innovations to increase performance, durability and productivity.

  • Horsepower 370-525 HP
  • Torque Range 1,250-1,850 lb-ft.
  • Displacement 12.8 L


Backed by years of proven performance, the new Detroit DD15 takes reliability, durability and productivity to the next level. Perfect for any operation, vocational or on-highway, the DD15 delivers everything you need from an engine, including greater profitability.

  • Horsepower 425-505 HP
  • Torque Range 1,550-1,850 lb-ft.
  • Displacement 14.8 L

Detroit Dd16

The biggest, toughest and most powerful engine Detroit has ever produced, the DD16® is the only 16-liter engine available. And since it offers the longest service intervals in the industry, it tackles your hardest jobs while increasing uptime and profitability.

  • Horsepower 500-600 HP
  • Torque Range 1,850-2,050 lb-ft.
  • Displacement 15.6 L


At just 2,050 pounds, the X12 is 600 pounds lighter than its predecessor, offering the highest power-to-weight ratio of any heavy-duty engine from 10 liters to 16 liters.

  • Horsepower 350-500 HP
  • Torque Range 1,250-1,700 lb-ft.
  • Displacement 11.8 L


With power and productivity, the Cummins X15 offers all-around performance with features like superior fuel and lube filter capacity that offer longer service intervals to optimize operational costs.

  • Horsepower 400-605 HP
  • Torque Range1,450-2,050 lb-ft.
  • Displacement 14.9L

Western Star provides a wide range of new vehicle engines compliant with EPA, CARB emissions, GHG, and OBD requirements.

Please consult your local dealer to ensure the selection of a product that meets your specific needs.



Detroit has taken the millions of hours of reliability of the DT12® automated manual transmission and engineered it into two new models designed and tested with vocational customers in mind -- the Detroit DT12-V and DT12-VX. Now your operators can enjoy the rugged performance of the DT12 in pavers, dump trucks, logging trucks and more, no matter what remote corner of the world they're working in.


Vocational Features


A wider overall ratio for improved startability and low speed maneuverability with a new planetary gear set design for greater input torque and GCW limits with improved durability.

Rock-Free Mode

Staying in drive and using the accelerator pedal gives the ability to break free from wheel-stuck situations and related downtime.

Off-Road Mode

Specifically designed to take on off-road driving conditions with optimized shift maps for extreme road conditions.

Paver Mode

The DT12-V and the DT12-VX enable a constant flow to paving machines by shifting from Neutral to Drive without depressing the brake pedal.

Bottom PTO

The DT12’s bottom PTO provides dependable performance and, when combined with the rear PTO, offers dual PTO usage that further increases job flexibility and application coverage.

Power Launch

Automatically increases engine speed up to 1,200 RPM during launch for smooth, powerful takeoffs with heavy loads while protecting the clutch and driveline.

Available Transmissions

To help you build exactly the truck you need, we offer a full range of both Eaton Fuller and Allison transmissions. To spec the exact transmission you need, find your nearest Western Star dealer.

Detroit Dt12-V

Automated Manual
Vocational Transmission

  • Torque Range up to 2,250 lb-ft.
  • GCW 160,000 lbs
  • Rear PTO Yes
  • Bottom PTO Yes

Detroit Dt12-Vx

Automated Manual Extreme
Vocational Transmission

  • Torque Range up to 2,500 lb-ft.
  • GCW 330,000lbs.*
  • Rear PTO Yes
  • Bottom PTO Yes

Eaton Fuller

Manual And Automated
Manual Transmissions

  • Torque Range 1,450-2,050lb-ft.
  • GCW 170,000.**
  • Rear PTO Yes
  • Side PTO Yes



  • Torque Range 1,250-1,850lb-ft
  • GCW 170,000.**
  • Rear PTO Yes
  • Side PTO Yes

*Application approval required over 160,000 lbs. **Application approval required over 170,000 lbs


Western Star logo that features 'Serious Trucks' in white text and a red star against a gray background.