You can use a set driven key for that Pixal. You create a controller like a locator and create a attribute say gearCtrl with a value range of say 0-50 and then you set a key with the gear in one position say retracted and the gearCtrl attribute at 0 and then move the gear to the extended position adjust all the bits and set another key for the gearCtrl set at 50.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675