Modern vehicles use a variety of fluids for the lubrication of their various mechanical components. Since many of the components are made of metal, they require heavy duty oil that is capable of protecting the components from damage due to overheating and metal-to-metal contact. Automotive lubrication fluids play a very important role in the overall performance and service life of a car and can cause components to become seriously damaged when they run low.
One of these types of fluids is the differential oil, also commonly known as gear oil, which is used to lubricate manual transmissions and differentials. Since gear oil is basically the equivalent of what engine oil is to the engine, it plays a very important role in protecting the differential and transmission, allowing them to do their jobs safely and smoothly. When the fluid gets dirty or contaminated it can put the components that it is meant to protect at risk of accelerated wear and even permanent damage. Usually bad or failing differential oil will produce a few symptoms that can alert the driver of a potential problem that should be serviced.
Vehicle has exceeded gear oil service interval
All vehicles come with a maintenance schedule for its fluids and filters that is based on mileage. If the vehicle has exceeded the recommended mileage for service of the gear or differential oil it is highly recommended to have it changed, as old oil may not provide the same level of protection as clean, fresh oil. If the vehicle’s components are ran using old or dirty oil, this may leave them susceptible to accelerated wear or even serious damage.
Differential or transmission are whining
One of the symptoms that is most commonly associated with bad or failing differential or gear oil is a noisy transmission or differential. If the gear oil runs low, or becomes excessively dirty, it can cause the gears to whine or howl as they turn. The whining or howling is caused by lack of lubrication and may increase in volume as vehicle speed increases. A howling or whining differential or transmission should be inspected as soon as possible in order to prevent the possibility of serious damage.
Differential / gear oil is just one of the various important lubrication fluids that many vehicles use in their normal operation, however, it is often one of the most forgotten fluids due to the fact that they are not serviced nearly as frequently as others. For this reason, if you suspect that your differential or gear oil may be dirty, contaminated, or past the recommended maintenance schedule, have the vehicle inspected by a professional technician, such as one from YourMechanic. They will be able to replace your differential / gear oil if necessary.
This article originally appeared on YourMechanic.com as Symptoms of Bad or Failing Differential / Gear Oil and was authored by Ed Ruelas.