Sounds like they are all Torque Converter Clutch (TCC) codes. CD4E uses an electronic torque converter for lock-up, not a fluid one as most other transmissions. And, as luck goes, an electronic clutch is more likely to fail than a hydraulic one. I am surprised that all these codes are all being set at once. It could be that the TCC is really in bad shape. I suppose it's possible that the pump failed and that took out the clutch. It's hard to figure out as I'm no trans expert.
As far as getting your oil changed every 3K miles, that is most likely the engine oil, not the transmission oil. The transmission oil is in a separate system. Have you had you trans oil changed before? I'm not sure what the actual recommended mileage is, check you owner's manual, but it's most likely around every 30K miles.
My 'tour sets a p0741 code occasionally, which will cause hard shifts. After the pressure drops down (usually within 1 day) all returns to normal. I have experienced this since I owned the car and I have had no real problems due to it. I am faithful to have the trans oil changed however.
I guess I would take the vehicle to another shop and get a second opinion.
