The transaxle key for the Merits Travel-Ease Commuter (P101) mobility scooters is the little steel piece that holds the hub tight to the axle and prevents the axle from just spinning freely. Not a big part for your scooter but one that makes a big difference!
Technically this half-moon style axle key is referred to as a Woodruff key to distinguish it from the more common square-diameter shaft keys. Woodruff keys are primarily used when the shaft is tapered for easier hub mounting or removal.
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