I have a 2.5L 95 Contour with 123,000 miles. I have the dealer chance xmission fluid every 40K miles but now it looks my transmission is starting to act up. In the morning I drive to work (55 miles all highway) and everything is fine. But on the way back (about 10 hours later) everything is fine until I hit traffic or get to a traffic light. When I come to a stop, I can feel a slight jerking before the car comes to a stop. When I acclerate again, there is a slight delay and then the car jerks forward and starts moving. The force of the jerking is directly proportional to how hard I step on the gas.

Any ideas what the problem might be? I checked the transmission fluid and it looks normal and the speed sensor was replaced about 4 months ago because it had broken inside the transmission.

Thanks for your time.