Allentown, Pa., and Greensboro, N.C. — Mack Trucks Inc., Allentown, Pa., has named Paul L. Vikner president and CEO, effective in early July. Vikner succeeds Michael Gigou, who will become president and CEO of Volvo Trucks North America Inc., Greensboro, N.C. Both Mack and Volvo are part of Volvo Global Trucks, Gothenburg, Sweden.