2001 Saturn SL1 Won't go into gear while cold

Do u have any codes in the transmission?Most likely u have ethier a low line pressure in the transmission. Or u could have a gear piston bleeding down. Also possible a loose input shaft nut common on those later models. It will have to be checked out by someone that knows saturn transmissions. There easy to work on but for some reason alot of people just cant figure them out. Even at the big chain transmission shops. Let me know what u find.