I just recently acquired a "like new" Bachman HO Doodlebug. It was still in the factory plastic wrap and was acquired from a deceased collectors display case. It seems to run great except it has a very loud clacking noise which sounds like there must be a bad spot on the drive shaft from the motor to the front truck. ANY SUGGESTIONS ON HOW TO CHECK THIS NOISE OUT? I understand it was very common on these early Doodlebugs. I could not find a video on YOU TUBE where this issue was addressed. It sure would make it easier if such a video does exist. ANY SUGGESTIONS WOULD BE APPRECIATED.....Frank UPIT