2005 Ford Taurus Wagon Transmission problems continue

I wrote in a couple of weeks ago saying that I had to replace the transmission in my 05 Taurus wagon at 83,000 miles. Had remanufactured transmission installed, after which car had a vibration that could be felt throughout my body. Same for passengers. Suggestion was that the engine might be missing, but after many tests and a tune up at the transmission place’s expense, could find nothing wrong with the engine. Also suggested it might be the Torque converter, so they replaced that. Still vibrates. Now, they will install another transmission and a fly wheel. Any other ideas what might be causing the vibration, which appears to be when the car idles or slows or at stop. Cld be that it is also vibrating when in gear but when car is in motion, can’t notice the vibration and may be because the engine is at higher performance when in gear. Car did not have this problem before the new transmission was installed. Any more ideas? Appreciate your thoughts.