im getting a PO743 code today. my truck started sputtering and then died. when i restarted it th service engine light was on. i took it to a mechanic and they changed transmission fluid, pan gasket, filter and added trans x atf conditioner. it has 146000 miles on it. did they perform the right work?

 

we--ll, no because the code indicated has not been addressed and wont be addressed by a fluid/filter change.
The code 743 is the converter clutch electrical failure.
This is not related to fluid. It is electrical.
The computer operates the clutch, as such, registers the code because it monitors the electrical 'current' signiture.
If the computer does not see the correct action, it is logiced a failure and you see/feel the resulting operational failure.
A trans shop is you next stop to address the code and not guess about it.
Good luck.