That's bummer because the codes can help verify the source of the problem. For instance, if they tell us it's the shift solenoids.
If you look on the sticker under the hood, do you see "OBD" or "OBD- II" certification? That should be near or on the vacuum routing sticker.
Maybe Transtar can provide you with an affiliated shop that will help diagnose the problem at a low cost (or even free). Transtar also sells rebuilt valve bodies and solenoids (not sure A540e series available). So you might want to check with them. An alternative is to pull one from the junkyard.