My 92 323 hatch has been having this problem for quite some time now. I'll accelerate and when my automatic transmission tries to change gear from 2 to 3 it will not. Instead the "HOLD" light on the dash board will begin to blink and the car will not change gears if i accelerate. The RPM's will increase but the speed will not go over 30mph. Then what i have to do is pull to the side of the road and shut off the car completely and then it usually will shut the "HOLD" light off and change gears when i accelerate. I've done a little bit of research and everyone says the transmission is going bad. My question is if i where to give the transmission a flush and change the filter, would this problem stop? Or should I just replace the entire tranny?

Any help would be appreciated, thanks