Now I'm supposed to pity you? You are clearly capable.
ALL you had to do was to list the car, the drivetrain, any custom electronics that were done to make it run, the last service you did and maybe a few other bits. Instead of that, you essentially wrote "Car no run. What should I do?"
The 545 uses a transmission control solenoid pack on the left side that is the entire brain for the transmission. Things like Low battery voltage, a pinched wire or a poor programming "tune" can mess with the function of the transmission.
I have replaced the solenoid pack in my 2007 Ram twice in the 381,000 miles I have on the truck. I have also helped others that had the solenoid pack go out. The pan comes off, the filters come out. The valve body is removed and then the solenoid pack is replaced. The last one was about $250 at a NAPA auto parts store or about $800 from the dealer.