Detroit DT12 automated manual transmission

The new DT12 automated manual transmission from Detroit Diesel is part of the Daimler Trucks North America subsidiary's complete powertrain offering that includes engines and drive axles. It combines the operational ease of an automatic with the efficiency of a manual transmission, the company says, bringing with it enhanced fuel economy and performance.

Available in the Freightliner Cascadia in 2013, first with the DD15 engine in late spring, later the DD13, it sports a lightweight design with its aluminum housing and single countershaft.

The 12-speed, direct- or overdrive transmission combines a traditional manual gearbox with high-speed, computer-controlled shift and clutch actuators that automatically select the right shift pattern and "perfect clutch engagement for fuel economy and engine power."

The DT12’s creep mode simulates a torque converter to improve low-speed maneuverability for parking, docking, heavy traffic, and other low-speed situations.

Features include Skip Shift, which automatically skips gears, enabling the transmission to run through lower gears faster to achieve cruising speed sooner; and eCoast, which allows the vehicle to ‘coast’ down grades with the engine operating at idle speeds while preserving vehicle momentum, maximizing fuel efficiency.

A proprietary control module communicates with the entire powertrain, giving the transmission and engine the ability to share information and offer complimentary functions. For example, the engine can limit torque to protect against driveline damage and harsh shifts, while the transmission can optimize shifts to keep the engine in the sweet spot.

Other features: helical gears and optimized gear-cut for noise reduction; pneumatic clutch and shift actuation for faster shifts; and a choice between eco or power-mode configuration. A kick-down feature improves vehicle acceleration when needed.

The DT12 comes standard with a 5-year/750,000-mile warranty, with a 2-year/200,000-mile warranty on the clutch.

It's also equipped with Virtual Technician, the factory-installed on-board diagnostics system that's said to take the guesswork out of powertrain repair. When a check transmission light illuminates, the fault is sent to a contact and the Detroit Customer Support Center (CSC) who can analyze the issue. The driver receives a service recommendation and the nearest authorized location with parts in stock.