Purely for amusement, yet it may have value for fellow members.
My C220 developed a ticking noise which was speed related, not showing until I reached 20mph, then the faster I went, the quicker the beat. The noise came from beneath the vehicle, yet the sound deadening is so effective, I wondered if it was a wheel, something on the brakes or suspension. Investigating time and again, nothing was found, yet the sound now pin-pointed to the back of the gearbox. Fear of a massive bill was setting in
Could it be the output bearing on the prop, maybe a UJ clicking away, still nothing after further inspection, the tension gathered momentum.
After getting the vehicle up on a ramp and removing the aluminium heat shield to 'again' expose the prop, I had the car in drive to spin the wheels! The culprit was identified at last. The bar code decal on the prop had half unstuck itself, the centrifugal thrust of the prop lifted half the decal from its adhered position where it would thrash against the cars underside, yet as the vehicle road speed reduced, the decal returned to its moulded form and looked normal.
I merely pulled the decal off, the problem went instantly. Worry about the worst, and the least happens!