Transmission Not Engage problems of the 2010 Dodge Caliber

The car has begun to shift hard and not engage immediately when trying to accelerate. This occurs worse in stop and go traffic, when the car is cold, and when driving up hill. I took the car to the dealer, a technician drove it and was able to replicate. He checked the transmission fluid, which was fine and decided it must be the motor mounts, but upon further inspection could not find a problem with them. He drove the car again and checked the transmission fluid immediately after stopping. The transmission fluid was foaming and he suggested a transmission service although the car isn't due until 100,000 miles and my vehicle is at 60,000. I had the transmission service done and the car appeared to be working properly for awhile, but is now exhibiting the same shifting/acceleration issues as it was before the fluid was changed.