I have a 66 6cyl coupe that has a considerable ammount of play in the rear axl when you turn the shaft. It bangs and jolts the car when I shift and when I brake. A friend says that it is "missing teeth". Seems to make sense, but I know little about the inner workings of a rearend. Does anyone know if this is common or if it sounds like what I have described is caused by "missing teeth"? A replacement seems easy enough to find and I have heard that to have one rebuilt is pretty steep. Any suggestions or clues would be greatly appreciated. Thanks.