For various tasks, it is necessary to unlock and lock the transmission lock.
This can be done from inside or underneath the vehicle.
From vehicle interior:
Underneath car:
Clamp lever firmly if permanently unlocking is desired.
Locking:

Fig. 52: Identifying Lever
NOTES ON MECHATRONICS (GA6HP26Z/GA6HP32Z/GA6HP19Z)
Special tools required:
IMPORTANT: After completing work:
Use only approved transmission fluid.
Failure to comply with this requirement will result in serious damage to the automatic transmission!
IMPORTANT: Read and comply with notes on protection against electrostatic damage (ESD protection).
Unscrew plug (1) and disconnect.

Fig. 53: Identifying Plug
Insert special tool 24 2 390 in sealing sleeve (1).

Fig. 54: Identifying Special Tool (24 2 390)
Replacing Sealing Sleeve For Transmission Housing (GA6HP26Z)
Torque Converter
Removing And Installing/Replacing Inlet And Exhaust Adjustment Units
On Right Side (N62/N62TU)
Removing And Installing/Replacing Exhaust Camshaft (N52K)