Overall truck production in North America is running 2.5 percent below the third quarter's average level, loss-making truck maker Volvo's chief executive said. CEO Leif Johansson also told Reuters in an interview that the group was in talks with potential buyers of its stake in rival Swedish heavy vehicles maker Scania.Volvo's shares extended earlier gains to trade 5.2 percent up at a six-month high of 173 crowns on Johansson's comments."In the third quarter the annualised pace of production was around 100,000 vehicles. Now this has fallen to some 97,000-98,000," Johansson said, referring to total output volume in the bellwether North American market.Volvo and rival truck makers have seen sales drop almost worldwide as a result of the global economic slowdown.Heavy charges for costs derived from plant closures and other measures to adjust output to weakening demand pulled Volvo's third-quarter operating result into the red."Customers in North America are postponing their investment decisions," Johansson said, adding Volvo's order intake was down. But he declined to say how Volvo's own North American business was performing relative to the overall market trend."In western Europe we can see a clear downward trend, above all in northern Europe and Germany. Southern Europe is also down but not as much as in the north," Johansson said.North America and Western Europe account for more than 80 percent of Volvo's sales.In March last year the European Commission blocked Volvo's planned takeover of Scania. The EU gave Volvo three years to sell its Scania stake, which corresponds to 45.5 percent of shares and 30.6 percent of votes.Asked whether Volvo was in talks with any potential buyers of the stake, Johansson said: "Yes." He declined to elaborate.German auto maker Volkswagen, which holds almost 19 percent of shares and more than one third of votes in Scania, is seen by many analysts as a candidate to buy Volvo's stake.Johansson said another alternative could be to distribute the Scania stake to Volvo shareholders.