The rear Differential is the final assembly to transfer power to the wheels. The design of it is to provide power yet still allow the vehicle to turn smoothly and ride comfortably. Most of the time you will never need to replace this component because they are usually built to last the life of the vehicle. The only maintenance required is a fluid change. When the fluid is neglected you will likely start to see failure of the bearings first. Tri City Auto Repair has all the maintenance schedules for your vehicle. Ask if you need a differential fluid change.