Transmission fault
A transmission code means the gearbox controller asked for a fault lamp or saw an incorrect gear ratio.
P0700 is a request to light the lamp; the detailed code is often stored in the transmission module. P0730 is an incorrect gear ratio.
Slipping, harsh shifts, or a flashing gear light belong with a scan that can read transmission codes, not only the generic P0700. The DTC pages explain that split.
A trouble code marks a condition to test. It does not by itself prove which part to replace.