When it starts off, in what feels like 3rd, that means the trans is in "safe mode". It usually relates to an electronic issue with the trans like a solenoid, sensor, or trans related circuit.
Make sure you translate the code and check everything related to that code to help you pinpoint the root-cause.
If it's a more mechanical-related issue with the trans, like bands or clutch wear, you usually won't get a code. If you don't repair the problem causing the safe mode and fault code, large mechanical issues (see catastrophic failure) will occur.