Transmission Tempature not shifing out of first

What is your question?

Hello I have a problem with the trans also I will give all it information and observations I see. First the trans will not shift out of what ever gear it is in most like first. Which when the gas is released it deccelerates immediatly. I drove out to a friend to check the computer and the whole ride there the trans was fine. He pluged in the reader and the code was fine. However all winter the trans was fine shifting like normal. Today it was 81F outside and the moment I started it and put the van in drive form park it jerked forward like it does when I have this problem and the whole day it was doing this. I was told about the computer and the sensors being an issue and some of the solinoids being stuck I want to get an idea before I drop the engine and trans. I feel it is temp related.