Vehicle drive wheel assembly

A vehicle drive assembly with a drivable wheel pivotably connected to a body, about an axis substantially transverse to the body, by first and second swing arms. One of the swing arms houses a motor and includes a heat dissipating member in thermally conductive association with the motor. The heat dissipating member preferably a plurality of cooling fins exposed to ambient air. The motor is housed in an end of the first swing arm opposite the body, and has a shaft that is directly engaged to a transmission within the wheel. The transmission is contained within a gearbox housing that rotates with the wheel and is formed by left and right structural gearbox halves. A wheel rim, configured to carry a tire, is attachable only to the first gearbox half, and can slide over the second half when removed from the gearbox housing, allowing the transmission to remain assembled. The interior of the gearbox housing contains a lubricant, and a vent is formed generally parallel to the motor shaft and extending through the first swing arm. Preferably, the second swing arm is detachable from the transmission while remaining substantially stationary in a direction substantially coaxial with the axle. Also, the transmission preferably includes a planetary gear reduction unit, in which planetary gears are mounted on a gear carrier that is configured to prevent rotation caused by the motor.