Rattle
Mine does the same thing. I even took it to see Fred Switzer at Paducah last year. He said "there is another place to oil, not shown in the manual, the crossover, underside of the machine. Oil that and it will quiet down". I oiled everything that looked oilable under there and it was quieter. I also put one of those Teflon washers in the bobbin carrier. That seemed to take up some of the slop in the bobbin movement and helped some. I also put rubber washers under the screws in the faceplate. They are vey tiny "O" rings. That even made more improvement. Be sure everything that can become loose is tight.
Good luck. You will probably find even more things.
Donna