2004 mazda 6i trans problems

mazda
mazda6

#1

I am concerned the mechanic who has my car is all talk. First concern, he tells me once the ATF goes out, scanner won’t give him a code. Is this true? He insisted right off the bat that he knew what my problem was, the main valve body. My gut told me not to leave my car with him, but the place had been in business since 1964. They wouldn’t be around that long if they don’t know their stuff, right?

History. I bought the car used last fall with 100,000 miles. Ran great. As it got colder started noticing shift shock. Learned that term on web. Seems to be common in these cars, so didn’t worry. 19 days ago car suddenly slips out of either 4th or 3rd gear. Had to get home, so took surface streets and it did not seem to be able to find 3rd gear. Found this local guy, seemed right at the time. Said it definitely wasn’t solenoids and had to be valve body and sent it in for rebuild. A week later after installing it was having the same problem so he sent it back again for another rebuild. Haven’t heard from him since. From what I’ve read on some forums, it really seems like the solenoids or computer programming problem. Do I insist on getting my car back? Do I pay for the rebuild if that wasn’t the problem. I want to say, “I will pay you the labor charge. Give me back my car” Is this right or wrong?