mercedes transmissions?

A common fault for non-shifting is a bad transmission valve body electrical plate.

Have a dealer or other trusted shop familiar with the Benz 722.6 electronic transmissions diagnose to confirm.

First check to see if there is any ATF in the transmission. If ATF is not up to the hash marks, add some ATF to bring the oil level to a normal operating position. Make sure the vehicle is on a flat and level place. If the transmission won't shift out of first gear, the gears may be broken or jammed. You had best find an automatic transmission specialist who can remove the transmission and repair it or trade it for a replacement/rebuilt/remanufactured one. There are many types of ATs, so be sure you have the correct model and the right person to deal with your problem. It will not be a cheap fix.