Answers to Important Questions about Car Differential Service

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Your car has an assortment of moving parts to enable motion, and most of these require service at scheduled times, depending on vehicle usage. However, many motorists don't know what the differential is and often forget to service it as required. This article outlines the importance of the differential and why it should be serviced regularly.

What does the differential do?

If you have to make a turn, your rear wheels don't travel the same distance – the left wheel goes a longer distance in a right-turn and vice versa. Therefore, the wheels must travel at different speeds to execute the turn smoothly. This is enabled by the differential – there's one at the front and another at the back – which delivers different levels of torque to the axle, allowing tyres to go at different speeds.

Why and when should the oil be changed?

Gears in the differential are immersed in differential fluid, which protects moving parts from excessive friction and the resulting heat and wear. Differential fluid is thicker than engine oil, but lighter than grease. However, high temperatures and contamination from normal driving breaks down the viscosity of the fluid and can prevent proper turning of the gears. This can cause greater damage to other parts, and even an accident during driving.

How often you change your differential fluid depends on your vehicle, anything from 65,000-90,000 miles. The differential has a fill hole, through which you can check oil levels. This can be done at your regular car service appointments, and your mechanic will tell you if the oil needs changing or refilling.

What are the symptoms of differential malfunction?

If left unattended to, you car's differentials may start to malfunction, and this happens in the following stages: