Ford Motor Co. is investing $3 billion to expand production capacity for one of its most popular and profitable vehicles.  The company announced on Thursday that it's adding its third North American assembly plant for its F-Series Super Duty trucks, its heavy-duty line of pickups. The plan will initially add capacity for 100,000 vehicles, Ford said.The plant, located at Oakville Assembly Complex in Ontario, Canada, is an effort by the company to maximize its manufacturing footprint and expand its Ford Pro c ...