I have a 04 pacifica and my problem is that when im decelerating and it shifts from 2nd to 1st the transmission hits hard. All the other gears shift very well. I can barely even feel the car shifting at all accelerating or decelerating until it comes to shifting down into 1st. The man at the auto part store said I should replace the synchronizer, which is a electronic part on the outside of the tranny. Its 180 bucks. Does this sound right.

 

its called a solenoid pack its possible that could help yes and if u have not done so filter and fluid as well

 

Mine has this same issue at times. I've chatted with "car guys" I trust (Both family, 1 trans 1 diesel expert) that said this is not really that strange, especially with the age. One of them actually like the strong jolt between gears.

If money's not a problem, which it is in my case, I don't worry about it. That's not to say I'm not concerned that it will eventually fail. I have 150K on mine and this strong jump only happens at low speeds when it's got to decide to downshift or stay in gear.

I would try the common services as stated in this thread. If that doesn't "fix" the issue, and it still bothers you, and money isn't an issue, try step two.