Stop, look and listen. Internal seal leakage does not produce external leaks. You could be leaking from a number of locations. Front seal on converter. The converter itself (including drain plug). Transmission cooling lines at the tranny. Take the car away from the guys who are currently working on it before you spend all of your retirement money. Get a hold of some ultraviolet dye used for chasing leaks in A/C systems. Clean up the transmission case as best you can (spray it off from below with carb/injector cleaner). Squirt the dye into the filler pipe and top up the fluid. Start it up let it run up to temp, go for a 10-20 mile drive and come back and look underneath with a "black light". If the leaks is still leaking you should be able to narrow down the point of origin.
2000 Dodge Grand Caravan SE