hi, it's clientside compatible??? thanks

The option will automatically appear in the action menu for certain types of vehicles (tanks, trucks, APCs, and other armored vehicles) when seated in the driver’s seat. You can find it in the action menu (mouse wheel) at the bottom, labeled Low Gear On.

Note that this feature won't work if you spawn directly in the vehicle in the editor. To see the option, you should exit and re-enter the vehicle, or spawn as a soldier first and then enter the vehicle.(Not a big problem for most of the mods/scenarios as long as you don’t spawn directly in the vehicle when the scenario loads.)

does this automatically come on or do you have to turn it on?