CROSS AND TRECKER <CTCO> BUYS AUTOMATION UNIT Cross and Trecker said it agreed to acquire the Alliance Automation Systems division of Gleason Corp <GLE> for an undisclosed amount of cash. It said the Gleason division manufactures automated assembly and test systems used in the production of small to medium size components for a number of industries, including automotive, electronic and appliance. Alliance Automation had 1986 sales of about 35 mln dlrs and employs 200.