HANOVER, Germany - (CORRECTED) Daimler Trucks intends to push for vertically integrated components in its American Freightliner and Western Star models, and next year will begin offering engine-transmission "modules" that promise greater efficiency for customers.

These will link Detroit diesels and automated mechanical transmissions that will deliver up to 7% better fuel economy than existing combinations, said Stefan Buchner, head of global powertrain procurement, manufacturing and engineering, in a briefing yesterday to trade-press reporters at Daimler's axle and gearbox factory in Kassel, Germany.

The heavy-duty DT12, a 12-speed ATM based on a Mercedes-Benz product from Germany, will be paired with the DD15 engine next May, the DD13 in November and the DD16 sometime in 2014, he said. Freightliner's Cascadia and other long-haul models will get the options. The DD15 will also use a "captive" turbocharger, but he didn't elaborate on that.

The push for more Daimler components in North American trucks began last year with Detroit-brand steer and drive axles, which are now standard on many Freightliner and Western Star trucks, though Meritor axles are optional. Detroit (formerly Detroit Diesel) makes the axles in Redford, Mich., outside of Detroit.

"North America is the only market using different powertrain brands," said Buchner in referring to the traditional practice of assembling trucks with components from outside suppliers as specified by fleet and individual buyers.

Customers on all other continents in which Daimler competes accept vertically integrated trucks where the original equipment manufacturer makes or controls what's installed. Daimler wants customers in the U.S. and Canada to do the same, and executives believe they will when buyers realize the benefits.

As an OEM, Daimler can offer greater efficiency and can better meet emissions limits because "we have all the software data in electronic controls, and we have the knowledge" of how to make them work best, as is done now in Europe and elsewhere with Mercedes-Benz trucks.

Its targets for proprietary product penetration in North America are 85% for engines, 60% for front axles, 40% for rears, and a longer-range goal of 15% for for transmissions, Buchner said. Detroit diesels have been standard in most Freightliners and Western Stars for some time, while certain Cummins diesels are optional.

Cummins also supplies natural gas engines to Daimler Trucks North America, something that's expected to continue because Daimler does not have its own gas engines for Freightliner or Western Star. Also to continue for some time is the use of Eaton heavy-duty manual transmissions and some AMTs.

Corrected 4:45 EDT 9/21/2012 to correct market penetration goals.