SOLVED: Where does "wave washer" go on blade adapter- Troy-bilt 860 series mowers

[GrowinWeeds]

SOLVED: Where does "wave washer" go on blade adapter- Troy-bilt 860 series mowers

EDIT: Never mind, found a schematic online, showing wave washer location (see 2nd attached pic).
Now, have to see if the washer's missing & the cause of it not changing speeds.
Thanks.
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Troy Bilt 860 Series, walk behind, self propelled.

While back, kid hit a root & I had to replace the flywheel key. No problem.
Recently noticed the transmission wasn't changing speeds when moved speed selector (engine running). I don't usually do the mowing - so didn't catch this earlier.

Mentioned in the manual is a "wave washer" that may come off w/ the blade adapter.
Then I remembered finding a wavy metal washer, about the size of a mower crankshaft, but didn't know where it came from.

From manual:

"Remove blade and adapter from crankshaft."
"IMPORTANT: A wave washer may come off with the adapter."
"Failing to replace the washer will result in mower not being able to change speeds."

If I take the blade & adapter back off and the washer's missing, exactly where does it go?
I'd guess under / inside the "blade adapter," but really don't know.