shifting problems on 2005 Lincoln Aviator

I had my transmission fluid changed at a lincoln dealer, and they added a detergent and conditioner to the fluid. After getting the car back I noticed the it was shifting hard from 1st to 2nd and from 2nd to third. I took it back and they say they drained about a pint of fluid and for about 25 miles it seemed to shift better, however it is now shiftinf hard again. They charged me $100 for this diagnoses and now they want to charge me again to recheck. Could the detergent or additive they added have caused this problem? The manual specifically advises not to add a cleaner or additives when changing transmission fluid.

Asked by for the 2005 Lincoln Aviator
It really sounds like they did some thing wrong, I would ask to speak to the manager. If your car was fine before they touched the transmission, they did something wrong.
1 more answer
I have an 04 aviator and in 05 they put in an additive as well and now in 2010 the tranmission is completely broken at only 47000 miles and the dealership will not take any responsibility. After they put in the additive the transmission kept having trouble shifting gears occassionally, I took the car back and asked them to look into and they kept saying it was fine until of course the warranty expired and my transmission died on me.