1992 Celica GT - Transmission Slip

[JJCelica]

Hi

I own a 1992 Celica GT. Just recently the car started to slip on first gear. I would be at a dead stop and when I accelerate the RPM goes up but the car does not pull as it used to. The gear is still engage just it does not pull as strong. Once it shifts to 2nd gear the car runs normal. Also, this only happens 1 out of 30 dead stops. And when it happens the O/D Off light (Over drive light) would flash ~ 80 - 100 times.

I figure it was maybe time to change the transmission fluid so I changed it and the problem still remains. I didn't change the tranmission filter (should I do that?). Or could this be a bigger problem? Thank you for your help.

Jake