Noise from transmission area

I “think” this pic is at driver’s side, front wheel well, wheel and plastic liner removed, looking in horizontally?

 

Yeah you don't need to be looking down there you're not looking at anything that needs to be seen that's just the side or the end of your transmission nothing's happening there stand up and look right in between the engine and the transmission put your hand in there if you like there's nothing moving you'll just feel vibration what's your feeling is an imbalance between the engine and the torque plate and more than likely the torque plate springs are slamming completely compressed and that's the rattling that you're hearing I do believe it's pretty common in this system it's a bunch of cow dung you can spend a whole bunch of money to keep the car if it's really nice but if it's got regular generation 3 problems probably not a thing to be doing but that's a personal choice I can't help you with.

 

Any follow up on this?

 

Is this the same car that had the bad head gasket that Medal linked to in post #5?

If it is the same car, did you replace the head gasket or replace the engine?

 

There is no torque converter in a Prius. What you do have is a damper between the engine and the transaxle. The damper springs could be damaged on your damper due to continued usage of the car when you have a bad head gasket.