What is the gear lever button on an automatic transmission car?

[LaZachary]

Automatic transmission car gear lever button is a lock button. When the switch is in the ON state, the high gear of the forward gear of the engine will be forcibly locked, which means that if it is a 4AT, it can only be shifted to 3rd gear at this time; Conversely, when the switch is in the OFF state, the gear lock will be canceled. The function of the lock button: to avoid the transmission making incorrect judgments in certain situations and frequently jumping between high gear and sub-high gear, it can be understood as a protective measure. The unlock button is a completely mechanical device. Press it with your thumb, and you can move the gear selector lever only after leaving the groove or stepping up the step. You don't need to press it when stepping down.