Hard shifts - possible transmission valve problem - fluid additives help, but keeps happening.

When I took my car to the transmission shop he said that the trans. needed rebuilt and that the computer was trying to compensate for the problem, that's why it shifts hard. He also took note of the dash lights that stay on all the time and he checked the codes for me. He concluded that the car had too many issues to fix and suggested that I "drive it till it drops and throw it away." I appreciate his honesty!

Problems with shifting all through town (when it's really hot) No one can figure this problem out. It's been in /out of shop times!