Ask any car expert and they will tell you that one of the most overlooked vehicle maintenance items among owners is knowing when or how often to change differential fluid. While we all know that motor oil is a top priority, neglecting your car’s differential and the oils that keep it running can quickly lead to an inoperable vehicle along with a number of costly repairs.
The primary responsibility of the differential—which is part of what’s called the “drivetrain”—is to help evenly distribute the vehicle’s power to each wheel, accommodating for the differences in which each wheel may be turning, hence “differential”. Think about turning the corner on your way home from work. As you make your turn, the two wheels on the outer part of your vehicle have longer distance to travel compared to those on the inside. Your vehicle’s differential is what allows your outer wheels to turn faster without skipping or hopping, or losing control.
While you may not previously have understood what a vehicles differential does, you have undoubtedly seen them. Ever noticed the large “box” or bulge in between the rear axle on a large truck or SUV? Then you’ve seen a differential. Differentials are found on every car and truck, whether you drive a two-wheel drive coupe or a four-wheel drive SUV.
In a front-wheel drive, the differential is often referred to as the “transaxle” because it shares the same housing—and gear oil—as the vehicle’s transmission. Four-wheel drives will have a differential in the front and rear axle while four-wheel drives actually have three differentials: one up front, one in the back and one in the center. Known as the “transfer case,” this part helps with differences between the speeds of the front and rear wheels.
To properly handle the even distribution of torque from your engine to your wheels, your vehicle’s differential is turning at speeds of up to 5,000 times per minute Metal gears operating in that capacity require proper lubrication to avoid wearing down and eventual failure which is where differential fluid comes in.
While your differential fluid and motor oils are equally important, one of the differences between the two is that your motor oil benefits from the use of an oil filter. Differentials are filter-free, meaning that should your differential start to experience unwanted friction—often due to poor fluid quality—it is likely that small metal shaving or pieces may appear resulting in significant damage to your differential. Various driving conditions, including different types of road services, temperatures and terrains, can lead to breakdowns in the quality of differential fluid—potentially causing premature damage. In the event of low differential fluid levels, the gears within the differential will begin to grind, causing your differential to fail and your vehicle to become inoperable.
As one of the most important components on your vehicle, the fluids that keep your differential running can be the, ahem difference between a smooth and safe ride. While each differential varies, fluids should be changed regularly and replaced with new differential fluids recommended by your vehicle’s manufacturer.