I agree with Pistole. It's nearly impossible for the bearing to be supplied with missing balls and if had been, you would have known it long before the mileage you accumulated. Usually bearings fail by overheating and eating the ball cage. Once that happens, the balls can disintegrate or pop out of the bearing. The process for assembling a ball bearing is to put all the balls in, then put the ball cage/spacer around them. Your missing balls are probably laying alongside the road someplace or in your wife's purse like most married guys. I got mine back as part of the divorce agreement, but I digress...