1996 Dodge Stratus Shifting Problem

Yesterday I was at a stop light and felt a hard shift while stopped. When taking off my car would not shift out of 1st gear, neutral, reverse all still work but for some reason it will not shift out of first also noticed that the PRN321 display on the instrument cluster does not show that it is in drive. Can someone please help me to try to fix this problem on my own or at least give me some info on it. thanks

I had the same problem w/ my car the transmission is intermitting its self and going into what they call safe mode. You need to get the computer for the transmission.