Why is my Transmission rev high from 1st to 2nd gear?

What is your question?

When I go to take off, the rpms go to the 3000 and If I take my foot off accelerator it'll kick into 2nd gear, the other gears change normal. And when the cars warmed up, the o/d off light comes on and message saying "check transmission!" Would that trigger my check engine light to come on? The code that came up is p0775. We changed transmission filter and fluid but that didn't make it better. Whats the next step that I can do without taking it to shop! Can't afford to take it to shop , any suggestions would help. Thank you