Self-detenting transmission shift key

An improved variable speed transmission of the type having speed change gears rotatably journalled on a shaft, a key slidably carried on the shaft for moving between the gears, means for coupling the key to the gears for rotating one gear at a time with the shaft, wherein the key has a bottom surface in sliding engagement with the shaft, the bottom surface of the key formed with a fulcrum point intermediate its ends about which the key pivots to engage and disengage the gears, shift means for moving the key relative to the shaft between the different gears to change the output speed of the transmission, and detent means for indicating different detent positions of the key in which the key is coupled to the various gears, wherein the improvement comprises detent means having a first detent portion carried on the bottom surface of the key and a second detent portion contained on the shaft, wherein the detent portions cooperate together to define the detent position, wherein the first detent portion is located at the fulcrum point of the key so as to engage the second detent portion on the shaft regardless of the pivotal orientation of the key.