2004 nissan quest

All the sudden, the transmission got stuck in “overdrive” or a high gear anyway, so a really slow get up and go. Everywhere said it was probably the transmission control module. So I changed the tcm, It drove fine for a few minutes the first day “I only drove it down the block and back”. The next day I started out in it running fine, but when I came to a stop and started to go it was back to the same thing, “stuck in overdrive” or possably safe mode? Any suggestions, It dosen’t seem to be total junk if it repaired itself even for a moment, right? Thanks