Troops tracked down and killed two Arab guerrillas who infiltrated Israel, attacked an Israeli truck with guns and a hand grenade and wounded its driver Wednesday, the army said. It was the second day in a row Arab guerrillas from Lebanon have clashed with soldiers inside Israel. The new attack occurred about two miles from Tuesday's border clash, in which two Israeli soldiers and three Palestinian guerrillas were killed, military sources said. It was not immediately clear if the guerrillas infiltrated Israel Wednesday or came with the group that entered from Lebanon Tuesday.