A system is provided for dissipating heat in an onboard non-engine powered aircraft wheel drive assembly with drive means that power one or more aircraft wheels to drive the aircraft autonomously on the ground without directly using the aircraft engines. The heat dissipation system is integral with a wheel drive assembly mounted substantially completely within a nose or main landing gear wheel. A reservoir mounted outboard or inboard of the wheel drive assembly increases thermal distribution mass and fluidically communicates with wheel drive assembly components to automatically circulate heat transfer fluid between the wheel drive assembly and the reservoir when the operating temperature exceeds a predetermined maximum temperature during aircraft ground travel. The heat dissipating system can be retrofitted in an existing aircraft to improve thermal distribution and prolong wheel drive assembly and drive means operation and useful life.