my 2001 mitsubishi montero sports suddenly stops on the freeway

my 2001 mitsubishi montero sports suddenly stops on the freeway off ramp exit, we tried to push the car towards the shoulder but it just dont move even its in neutral, it seems everything is locked im guessing its the transmission, i can start the engine on but the car just wont move even its on drive mode(even on 2, 3 or L mode) hands brake is off, put new transmission oil in it just didnt help, does it have something eletronics or eletrical needed to fix my car? besides the transmission i can think of, trying to save some money before deciding to replace transmission because before after replacing the battery the engine keeps dying and it takes a while the car to reset on its original setting, hoping there's only electronics or electrical issue on my car thats why its not moving...please help