Yes, I had a big scare one hot day in a traffic jam. It would not "grab", and could hardly go up the exit ramp. Also the up-shift arrow (for overdrive) kept flashing. I found that when I started the car in neutral, it was ok. I parked the car until late night, then drove it home when it got cooler and with less traffic. The next day, I had the fluid changed by a trustworthy mechanic, and the problem never surfaced again. Strange.

Good Luck.