Jayanidu Udana

Hi All, I have a 2001 Bluebird Sylphy G10.Auto When i starting the car gear,not working in drive mode.then gear shift to 1 and after 2 min car will appear drive mode ,after runing 5 minutes or some km car is working on D mode. For a solution I change the ATF oil ( cleaning drain plate ,filter plate also ) by tecnician. In that moment issue is clear , but after 5 hours the issue is same , I need to sort out this issue immediatly. Please comment.thanks..