We had the need to get some replacement Fisher Price motors and the Power Wheels Service Center that I went to could not match up the part number for the Fisher Price Motor (RS550PF-6534). They also could not match any of the numbers stamped on the motor housing. I was forced to buy the motor from last year with the 16 tooth pinion. Can anyone tell me what the cross reference number would be so that I could buy the new motor? The only difference appears to be the fan vents on the back and the pinion gear. Thanks.