Welcome to the forum!
The 3-point going down is pretty normal. My Deere does the same.
On the rattling noise, is it coming from inside the rear-end of the tractor or is it in the PTO shaft itself? With nothing connected to the PTO on the tractor, does it make that noise when you engage? Rattling in my experience is normally in the PTO shaft and it's related to the U-joints not being lubricated or failing.