Was told needed new transmission. But, could probably drive by manually shifting

What is your question?

Automatic transmission. Won't exceed 45 MPH. Felt trans slipping, but Non I do not feel it slipping. Seems to be running ok? But, still don't want to go over 45! Is it possible the trans could have "fixed" itself? I start in 1st, go to 20mph and put in 2nd, then around 30 mph go to Drive. Seems like it is ok now?