It is a harmonic vibration. Don't beat the exhaust with the mallet, that us how the core material in the exhaust cracks. The plate is just an inspection cover and it is how we used to access the converter nuts on the old Fords. I would probably try a popsicle stick in between the plate and bell...
Take the cover out and see if it goes away. If it does, bend it a tad and that should fix it. Or maybe jam a rubber ball between the pan and the cover and try again. Just don't leave the ball in there when done.
Are you trying to justify saving a few bucks vs. blowing up your engine? What is the difference in cost? Gears are probably less expensive than a new engine but I am just guessing. Skinflinting here is not in your best interest. Curious as to how old you are. Really not putting down your...
If this were a typical V8 I would say go for it. I have built 335 series engines in the past and woild be very cautious with a Coyote, even if was a spare that was just for experience. And I say this as a once certified ASE guy who went to voc school and then years building at Aamco.
If you...
I will just reset the monitor. Unfortunately, my mileage this year will be on the low side due to major surgery on my better half real soon. The car is the least of my worries and I posted the thread more for shits and giggles than starting any battles over maintenance. Without your health...