A lot of the time with these gears you won't even see the crack as they are sometimes so slight but they will slip. Make sure the Gear pictured does not slip on the metal shaft as this is the one that moves back and forth to engage the wheels with the on/off switch. That white, round, non-gear thing to the right of it is the method that the switch uses to move that drive gear into messing with the axle gear. Speaking of the axle gear...is it firmly on the axle and doesn't slip?
I believe there would be a gear (not pictured) on the motor shaft too...right. Make sure that on is on tight and can't be pulled off easily. Sourcing replacement gears is troublesome. Probably the only gear that can be found is the one on the motors shaft. Other gears can be sourced from not wanted or damaged other motorized vehicles that could be picked up cheaply especially include in 'Lots' for sale or found at the Thrift stores. The all pretty much use similar gears so that should help if one is needed. I wouldn't think there is any problem with that middle gear as its all one piece including the axle so that limits looking for which one or ones need help with.
I believe there would be a gear (not pictured) on the motor shaft too...right. Make sure that on is on tight and can't be pulled off easily. Sourcing replacement gears is troublesome. Probably the only gear that can be found is the one on the motors shaft. Other gears can be sourced from not wanted or damaged other motorized vehicles that could be picked up cheaply especially include in 'Lots' for sale or found at the Thrift stores. The all pretty much use similar gears so that should help if one is needed. I wouldn't think there is any problem with that middle gear as its all one piece including the axle so that limits looking for which one or ones need help with.