i just bought a 2003 grand caravan, 3.8L, and im having some shifting problems. when accelerating from a complete stop, and when the transmission changes from 1st to 2nd gear, there is a shudder. it feels like the transmission is changing into 2nd, then back, then into 2nd, then back, then into 2nd, and it will finally change all the way and accelerate through the rest of the gears just fine. It is a violent shudder. no noises coming from transmission though. i have no check engine light on, and no codes. i have changed out the throttle position sensor with a brand new one, and cleaned the throttle body. i have changed the oil and filter in the transmission, and used the proper atf+4 oil, and filled to correct level. problem still persists. i got a bottle of lucas transmission fix, but that didnt help either. in fact, made it worse. right after i put the lucas in, i developed a new problem. now, when decelerating, and the transmission shifts from 2nd to 1st, the car shakes as if it was a hard downshift, and you can hear a "thud". so now i have both problems. i have double checked all the electrical connections including the input and output speed sensors, and the tcm wiring, everything looks good. I have ordered a new shift solenoid pack, and will change that as soon as i get it. does anyone have any ideas as to what else it could be????