Ford Motor Co.'s new diesel and gasoline engines for its revamped 2011 Super Duty pickups are cleaner, quieter and more economical than current products, executives said at a presentation at the National Truck Equipment Association's annual meeting in St. Louis.

The 6.7-liter Power Stroke diesel and 6.2-liter gasoline engine, both V-8s, will be the optional and standard engines, respectively, in F-series heavy pickups when they go into production later this year with revised front-end styling and more comfortable interiors.

The Ford 6.7 diesel will replace the last Navistar-built diesels in conventional-cab Super Duties after that long-running supply agreement ended in December. The new Power Stroke can burn biodiesel up to B20 and will be up to 25 percent more fuel efficient than the old engine, said Doug Scott, truck group marketing manager. It makes as much as 390 horsepower at 2,800 rpm and 735 pounds-feet of torque at 1,600 rpm. It will be available in F-250, 350 and F-450 pickups and F-350, 450 and 550 chassis-cab models, and the upcharge for the diesel will be unchanged from the current list price of about $7,400 over the standard gasoline engine.

The 6.2 gas engine's rating is 385 horsepower at 5,500 rpm and 405 pounds-feet at 4,500 rpm, and it can burn ethanol-gasoline blends up to E85. It will replace Ford's 5.4-liter Triton V-8 in F-250 and F-350 pickups, and will be 15 percent more economical than the 5.4.

Half the fuel-economy improvements in both the new engines come from double-overdrive gearing in a new 6-speed TorqShift automatic transmission, according to Al Bruck, transmission engineering manager. It's based on the current 5-speed TorqShift, which continues with other engines. The 6-speed has a stronger torque converter that locks as low as 900 rpm, about 200 rpm less than the 5-speed, for less hydraulic slip and better fuel efficiency. The 6-speed has live power take-off capability that allows operation of dump bodies, liquid spreaders and the like on the go as well as while stationary. Extensive attention was also given to shift points and pump pressures to maximize efficiency.

The 6-speed transmission, called 6R140, is about 25 pounds lighter than the 5-speed, Bruck said. The 6R140 has a 150,000-mile fluid change interval, which is two and a half times greater than the outgoing product, with no break-in change needed. A patent-pending high-efficiency dual-media filter, mounted internally to reduce the chance for leaks, is the main reason for the extended maintenance interval; long-life fluid is another.

The new 6-speed has a deeper low gear that allows easy starting of heavy loads, Bruck said. With it and the new diesel, Ford Super Duty models claim best-in-class towing ability - up to 26,400 pounds - and a 6,520-pound payload capacity. Fuel economy should also be better than competitors'.

The new V-8s were designed by Ford engineers and are being built in Ford factories, the diesel in Mexico and the gas engine in Michigan, executives said in this and previous announcements. Ford's development of its own V-8 diesel, allegedly in violation of the supplier agreement with Navistar, was part of the dispute between the two companies; the original point of contention was high warranty claims on the Navistar-made Power Stroke diesel that was new in the 2004 model year. Ford and Navistar sued each other, and settled by ending their supply arrangement as of Dec. 31.

The 6.8-liter Triton V-10 with a 5-speed TorqShift will continue as the standard engine in heavier F-series pickups and cab-chassis models, as well as a new F-59 stripped chassis announced a year ago that enters production in April, and in an E-series vans and cutaway chassis.

2011-model E-series will also be available with the 5.4 gasoline V-8, but no diesel engine because the new 6.7 diesel is too large for the E's engine bay. Ford executives are pondering how to replace the 6-liter version of the Navistar diesel when stocks run out. It's possible the E will not get another diesel, because Ford is rumored to be close to announcing that it will bring in its large Transit van from Europe, which uses smaller diesels.