I wonder if it’s possible for a creature to have axles and some kind of differential?
The "gears" on this insect are basically intersecting teeth on two otherwise normal leg parts. Evolving an axle or any other free spinning part would require disconnected parts. The external parts would be cut off from any metabolic functions of the main body. Nothing remotely like that has ever evolved before so it would be nigh impossible.
Colonial animals are the edge case here. Most would be hesitant to say an ant colony is "an animal", but are happy to refer to a Portuguese Man 'o' War as such, despite also being a colony.
Man o Wars are also not disjoint. They have specialized cells, but I believe share nutrition among the non-feeding cells. A truly disjoint creature would need a metabolic system on both sides of the disjoint, a separate nervous system, and perhaps most difficult, a way to pass messages across the disjoint quickly enough to be useful (aka electric impulse).
At a certain point, I think it starts becoming dubious whether it's a single creature. Even if they're genetically identical, they start to look more like twins than a colonial creature.