Vibration is helpful when its coursing through the foot massager that you picked up from Brookstone, but it's downright harmful when it's rattling through your engine block. That's why engine engineers developed various parts to cut down on vibration, including your balance shaft gear case. If your stock balance shaft gear case is too shook up to work properly, replace it with an OEM-grade new balance shaft gear case from AutoAnything. Along with free shipping, you get a 1-year lower-price guarantee with your new balance shaft gear case.