You might wonder what a rear differential is. Simply put, the rear differential on most cars and trucks takes power from the vehicle’s transmission and turns the rear axles (wheels attached). The rear differential allows the wheels to turn at different speeds (for example one wheel turns faster than the other when making a turn).
The gear oil in your rear differential keeps friction to a minimum and ensures the long life of your differential gears. Gear oil lubricated differentials are found in two-wheel drive and four-wheel drive pick-up trucks and SUV’s, as well as in rear wheel drive passenger cars and vans. Although periodic replacement of the gear oil is specified by vehicle manufacturers to maintain the performance and longevity of the differential, this is probably the most commonly overlooked service in personal transportation.
Not servicing the differential can lead to gear oil breakdown, cause poor differential performance and noise. If not properly maintained there will be excessive wear and corrosion of the gears leading to failure (break down).
Vehicles carrying heavy loads or pulling trailers need additional servicing. The replacement cost of a rear differential can easily be in the thousands of dollars. And that is not mentioning the dangers and inconvenience of being broken down on the side of the road.
YOUR VEHICLE MANUFACTURER SPECIFIES WHEN YOUR DIFFERENTIAL REQUIRES A FLUID CHANGE.
Unlike your vehicle’s engine the differential does not have a filter. Typically there is a magnet that catches as much of the metal shavings and metal parts as it can in the rear differential. At some point these metal flakes or shavings can and will damage the metal parts in your vehicle’s differential.
Conclusion. It’s your vehicle. Read your owner’s manual and learn what the manufacturer says needs to be done for your vehicle’s rear differential. Even though you may not even know what it is or looks like it is a very expensive component of your vehicle and it has to be maintained to avoid failure and costly repairs. If one of our technicians tells you that you need the rear differential fluid changed it is because your vehicle’s manufacturer says it needs to be done.
Not convinced? Google Metal Shavings in Differential and Metal Flakes in Differential.