2000 Other Saturn Models can't shift gears

I have a 2000 Saturn LS1. Up to now has run great. Lately having trouble shifting from a stop. Both from an initial start up and when stopping at a light. While driving it seems to shift ok. But when I first start it I can't shift out of 1st. I have been putting it in 2nd, start the car and drive.. once a little speed is built up it shifts ok... when I come to a stop sometimes it is hard to down shift. It is not constant.. but seems to be more when the car is cold (1st thing in the morning). I took it in to a mechanic but of course he couldn't duplicate the problem... Any suggestions??? Oh yeah I forgot... if the car is turned off.... shifts easily.