Potential whine from rear wheel

[Grumpy Goat]

UPDATE (a bit): Changed the final drive oil--no bits, no bright metal flakes, just normal sludge at 4K on that oil. Will ride it tomorrow (things got in the way). Have an action camera mounted near the FD. We shall see.

Sounds like a good plan. Glad to hear that oil came out. I guess you didn't measure it? Chances are if there were no signs of leak then it would likely have still had the 180 ml of gear oil. The action camera mic should pickup any whine that you would have heard farther away, and through earplugs. Hope you hear nothing tomorrow.