1998 Caravan, transmission fluid comes out of dipstick tube

I have a 1998 Grand Caravan with around 150k miles on it. About a month ago, the transmission went into limp mode and it was determined that the solenoid pack went bad. I had it replaced and while the mechanic had the vehicle, I had him change the fluid and filter. The vehicle seems to shift great now. However, when you get out on the highway and run for several miles and then come to a stop, smoke will just roll out from under the hood. This transmission fluid is coming up through the dipstick tube. When this first occurred, I check the fluid level and it was just a little too full. I assumed the fluid was coming out because it was too full and would stop when the level came back down. We went out of town this weekend and when we stopped, it did it again. I checked the fluid and it was now low. This vehicle has the 41TE transmission. It appears from what I can read about it, the transmission vents through the dipstick tube. Does anyone have any idea what the problem may be.
Thanks

The filter may have been installed improperly, with 2 or no O rings at the sealing surface, causing the fluid to aerate and foam up. Yes, trans vents through dipstick tube (seems like thats working ok).

Thanks for the response, I will give that a try.