Rocket Fuel

Cummins ISX15. Fuel Economy Plus Performance.

Since its introduction, the Cummins ISX15 has been the transportation industry’s leading choice for fuel efficiency and performance. Our relentless quest for improvement has resulted in double-digit gains in fuel economy, as seen in the chart.

As you can see, the SmartAdvantage Powertrain was a key contributor to increased fuel efficiency, particularly in OTR trucking operations where the small-step overdrive transmission yielded the greatest benefits.

Today, with the launch of new direct drive transmission options for the SmartAdvantage Powertrain lineup, less-than-truckload (LTL) and regional-haul operators get a spec ideally suited for duty cycles with multiple delivery stops and lower average road speeds.

A total of six ISX15 SmartAdvantage Powertrain options are now available:

Transmission Top Gear Cummins Engine Power hp (kW) Peak Torque lb-ft (N•m) @ rpm Eaton Transmission Model Axle Ratios
Small-Step Overdrive ISX15 400 SA 400 (298) 1450/1650 (1968/2240) @ 1000 FAOM-14810S-EC3 2.78
ISX15 400 SA 400 (298) 1550/1750 (2103/2375) @ 1000 FAOM-15810S-EC3
ISX15 420 SA 420 (313) 1550/1750 (2103/2375) @ 1000
ISX15 450 SA 450 (336) 1550/1750 (2103/2375) @ 1000
Direct Drive ISX15 400 SA 400 (298) 1550/1750 (2103/2375) @ 1000 FAM-15810B-EA3 2.26
ISX15 450 SA 450 (336) 1550/1750 (2103/2375) @ 1000

The ISX15 SmartAdvantage Powertrain using direct drive transmissions are designed to maximize fuel economy in specific duty cycles and operating conditions – some regional haul or LTL truckers will see better results using the small-step overdrive transmission. This chart shows the benefits of each:

Condition Direct Drive Overdrive
Higher Efficiency In Top Gear Conditions
More Even Steps, Easier To Drive (With Manual)
Downspeeding Capability
Higher Gradeability And Startability In Low Gears
Less Prone To Driveline Wear

To learn which SmartAdvantage Powertrain is right for you, click here.

Cummins ISX15: Redefining Efficiency.

Cummins is continually setting new benchmarks for the trucking industry. Major technological advancements in the ISX15 platform include ADEPT with with SmartCoast and SmartTorque2 (ST2), along with Vehicle Acceleration Management (VAM).

This video explains how ADEPT technology works, and previews new technologies to come.


The Ultimate Customer Advantage.

The video below is a customer testimonial from Central Trucking Inc. (CTI) explaining how the ISX15 SmartAdvantage Powertrain has delivered three-quarter MPG improvements for the business, and has been a hit with its drivers. You can also read more about CTI's experience operating trucks with the SmartAdvantage Powertrain at our Cummins Engines Blog and see why CTI is transitioning its entire fleet to the ISX15 SmartAdvantage Powertrain.



To learn more about the proprietary technology, features and specs of Cummins ISX15 engine including the XPI Fuel System, VGT Turbocharger, the fully integrated aftertreatment system and more, check out

For additional details about the Eaton Fuller Advantage® 10-speed automated transmission, visit Eaton Heavy-Duty Automated Transmissions.