A $2 million donation from a Bellevue-based company that specializes in designing long-haul trucks is helping Gonzaga University build a new science center that will expand the school's engineering programs, the school said Friday. The donation from Paccar Inc. will cover about a quarter of the cost of the new $7.9 million Paccar Center for Applied Science, which is scheduled to open in time for classes in fall 2008, GU said. The 25,000-square-foot building will be just south of the Herak Center for Engineering, with construction set to begin in the spring.