Q: Transmission

The check transmission light came on with a flashy light. Then it goes a way. When I press the gas pedal the vehicle stalls and doesn't want to shift to the next gear but eventually goes to the next gear. I drove it for roughly 2 1/2 weeks and the light comes on only 3 times but goes away. When I am at a stop light or stop sign and push the gas vehicle is slowing moving forward and stalls to the next gear and once accelerated it continues to stall to the next gear. Took the vehicle in for diagnostic but mechanic ended up changing oil, brakes and put transmission fluid flush. It still appears the same problem. I have an extended warranty. Mechanic gave them codes 731, 732 and 734. Warranty now wants mechanic to break down the transmission to find a root problem and will send out an inspector. What should be done? Should I take it to a Lincoln Dealership? I may have to foot the current mechanic bill for removing transmission went isn't right. 2005 Lincoln Aviator AWD only 107,700 miles.

My car has 107700 miles.
My car has an automatic transmission.