Transmission problem

Hello all. I am new to this forum. I own a Santa Fe 2003. I am experiencing a problem with my transmission. In the morning the transmission is stuck on Gear 2 when it is on drive position. After about 10 to 15 minutes of rolling on the road the other gears are so to speak unlock and the transmission is working ok the rest of the day. Is that dangerous for the transmission and how can I fix the problem.

Thanks for any help

mine does it to...the trick is to let your car run for 5-10mins before driving...letting everything warm up....and yes it is bad to not let it warm up.