OK so two days ago I noticed this rattle coming from the engine. Kinda sounds like rocks in a can, at first I assumed it was because of an oil deficit but oil was fine. It sounds like it's coming from the driver's side in the cat area but my buddy thinks it's coming from the transmission. I'm going to take a more in depth look tomorrow but what wanted to get your thoughts. It starts to get audible around 2700rpm and stays audible until 4200 and gets drowned out by the exhaust.

I've posted a link to the a video where you can hear the rattle.

https://youtu.be/8bO0CyyL4to

Thanks for the help.