The 40-day labor strike made a big dent in GM’s bottom line. The automaker said the walkout that virtually halted all North American operations would cost it around $3 billion in profits this year. As a result, General Motors is slashing its earnings forecast for the full year. Last Friday, union members made peace, ratifying a new four-year labor deal that wrung higher pay and other benefits from GM. The automaker’s CFO described the strike as a “one-time impact.” GM shares rose sharply Tuesday. investors applauded the company’s robust 6% sales gain in the United States. Its highly profitable pick-up trucks, sport utilities and crossovers drove the top line higher. Profit fell, but it STILL crushed analysts’ expectations.