Help with 95 RS automatic transmission

Hi I have a 95 RS eclipse n/a. The auto trans is dropping down into 3rd on freeway or will will slip out all together into neutral. If you turn car off and re-start, the car will continue. It only does it during the day and not at night. Car is killin me. Is fluid getting hot? I just change fluid and filter but no flush. I dont want to flush it unless that 100% of problem. Help please..John.. Yahoo messanger john67elco