Heat from friction will gradually cause the differential fluid to break down, making it harder to keep the differential properly lubricated. Degraded differential fluid causes poor differential performance, excessive noise, and disproportionate wear. In severe causes, old fluid will eventually cause a differential breakdown, if not a complete differential failure, which means that your entire differential system will need to be replaced. Replacing an entire differential system is costly and can be avoided with routine maintenance as indicated by your owner’s manual, which will provide you with specific intervals for servicing your differential. Depending on your needs, when you undergo a differential service, various components of your differential system will be checked and possibly repaired or replaced in order to keep your vehicle running efficiently.