tires or dealer

What is the name of your state (only U.S. law)? pa
we recently purchased 2 new tires for our ford explorer from goodyear(tires they said we needed) after several trips to different for service centers we found that what we thought was engine trouble was due to the wrong size tires being put on. damaging the transmission and transfer case. who is liable here ? goodyear tire center, the first ford service center who found "no problem" or us !? please help
thanks

Sue the person who damaged the car.

Bad bad apples .....