Transmission fluid leak

Hello. I have an 07 Tundra V6. I purchased in 08. I started doing my own maintenance a couple years ago. I am getting code P2757 for Torque Converter Clutch Pressure Control Soleenoid. I was under my truck and noticed transmission fluid on the pan and around. I haven't noticed any pooled up fluid. I think it is leaking while running since I found 4 bolts missing around the pan. I also found a check plug and drain plug. Where is the fill? What happened to the bolts? The code recommended replace transmission shift solenoid and flush. Should I take to dealer or handle myself? Thanks for your time.

 

On the 5.7L engine the fill plug for the transmission is on the driver side, pretty high up. Its just a bit back from the pan if I recall correctly.