A milling machine (20) for milling a surface of a roadway includes a frame (22), a housing (24), a milling drum (30) mounted on the frame (22) within the housing (24) and a drive assembly (26,28). A positioning assembly (36) is provided for moving the drive assembly (26,28) between a first position which is laterally outside the periphery of the machine housing (24) and a second position which is laterally inside the periphery of the machine housing (24), and for locking the drive assembly (26,28) in at least the first and second positions without requiring the operator to manually manipulate a locking pin. The application discloses also a method for moving a drive assembly of a milling machine.