2002 Ford Windstar Transmission crashed after replace engin

I understand your problem and will offer you two different perspectives. The first is from the view of a consumer. It is hard to believe that a trans can fail so soon after replacing an engine. There are two issues to be delt with here. The first is that if nothing else the shop should have noticed the condition of the trans fluid and recommended a trans service or flush. The second is the possibility that during the removal of the engine the torque converter (which bolts up to the flywheel on the engine) may have been stuck to the flywheel causing it to separate from the trans shaft. If this happened, it is possible that the torque converter damaged the seal. It would, however, be hard to prove that this happened. The second perspective is that of a professional technician. I would assume that the engine was replaced because it had overheated. If this is true, understand that the cooler lines for the trans run through the radiator. If the engine was hot so was the transmission. I recall one instance where I rebuilt a 3.0 engine because it blew a headgasket. When I installed the rebuilt engine I took it on the TEST DRIVE only to have the trans go out on the test drive. That was a difficult conversation to have with the customer. But it is an unfortunate reality. Sometimes this happens. It doesn't excuse the responsibilty of the shop to notice the condition of the trans fluid or take extra precautions to minimize the chance of this happening. It is possible that the cause of this was their fault, but only if the torque converter damaged the front seal. I would be glad to try to answer as many questions as you may have on this concern or any other. Thanks
Dave

Was the trans fluid pouring out between the engine and trans underneath? If so, I would argue the case that they may have damaged the seal when separating the engine from the trans. If it was spewing out of the top, it overheated, in which I would argue with them about not checking the trans fluid level or condition. Or at the very least, that they should have said something to you about the color of the fluid. Since the engine and trans are both dropped out through the bottom of the vehicle in the subframe, they would have had to have disconnected the trans lines. They would have seen the fluid and should have topped it off. Check with them to see what exactly they did with the trans fluid before the test drive.