NEW YORK ( TheStreet) -- Ford Motor has much to prove to shareholders about its bold decision to redesign its top-selling F Series pickup trucks with an aluminum body rather than steel. F Series pickups are responsible for about 90% of Ford's profit. Switching manufacturing processes and the delays transitioning from the incumbent pickup to the newcomer have been costly -- the specifics evident today in Ford's fourth-quarter and full-year 2014 financial results.