DETROIT (AP) – Ford Motor Co. is offering a diesel engine in its F-150 pickup for the first time.Heavy duty trucks like the F-250 or F-350 have always had diesel engines, but full-size trucks like the F-150 have not. Ford is hoping to gain some customers from rivals Ram and Nissan, which both offer diesels in their full-size trucks.The F-150 is the best-selling vehicle in the U.S.Ford expects the F-150 to get 30 miles per gallon on the highway with the new 3.0-liter V6 diesel and a 10-speed transmission. That’s 4 mpg better than the current most efficient gasoline-powered F-150.The company offers six engine choices for the F-150. It says the diesel is targeted at customers who tow or haul big loads and want better fuel economy.Ford expects around 5 percent of F-150 buyers will opt for the diesel, which costs $4,000 on the Lariat and Platinum versions or $3,000 on the King Ranch.Here are more details about the F-150 diesel:– Customers can order a diesel F-150 starting this month. Deliveries will begin in the spring.– The diesel will put out 250 horsepower and 440 pound-feet of torque.– It can tow up to 11,400 pounds and has a 2,020-pound payload capacity.– Ford says the team that designed the 6.7-liter Power Stroke V8 diesel for its heavy-duty trucks designed the engine for the F-150.– Retail customers can only get the diesel on higher trim levels. Fleet customers will be able to opt for it on the lower XL and XLT trims.