95 cougar transmission problem

[graberm]

Hello,
I was wondering if anyone had an idea of what is wrong with my car. A couple of times now it has not upshifted at all as I drive to work in the morning. So when I was going 50 at 3000+ rpm, I pulled over for a while and started it again and it returned to normal. I checked the transmission fluid, there is plenty and it is clean (just had it flushed this past summer). Mostly I just want to know if it is something really expensive to fix, in which case I would probably just live with it until I can get a new car.

Thanks,
Mindy