Back to all

Gearing Up (Differential Fluid Service)

January 18, 2026

You may have never thought about it, but when you turn a corner, the wheels on one side of your vehicle turn at a different speed than the other side.  What is this magic? The answer is something called the differential.  

A differential is a gear box placed between the drive wheels and needs lubrication to work.  Over time, that fluid can become contaminated, reducing its effectiveness. You likely won’t be able to detect any signs that it’s happening, though it may get a little noisier over time. 

If you continue to drive with contaminated and degraded differential fluid, the gears may wear prematurely. That can also contribute to excess wear on the drive-wheel tires.   

Two-wheel drive vehicles have one differential while all-wheel and 4-wheel drive vehicles will have two or three.   Your vehicle’s manufacturer has guidelines on how often you should have the differential fluid changed, and we recommend you follow those.  

Changing the differential fluid is different depending on what model and year of vehicle you own.  Some have a drain plug so the fluid can be removed and replaced.  In others, a cover and gasket on the differential will have to be removed and replaced.  

Because differentials have constantly moving parts, they generate heat.  That’s why some have a vent to help dissipate the heat caused by friction, and sometimes that vent will need replacing.

When you bring your vehicle in for differential fluid replacement, our technician will also inspect the differential for other issues and test drive it to make sure it’s operating the way it should.  

Tuffy Joliet (South Plainfield)
2031 SR 59
Joliet, Illinois 60586
815-436-1829

More articles from Tuffy Joliet

Not So Hot in Joliet

January 11, 2026

When the weather turns cold, it's nice to crank up the furnace and enjoy the heat. But if your home's furnace doesn't work, it's not too comfortable. Same goes with your vehicle. When the heater's not working, things can get miserable. It could also signal some major problems, which we'll discuss... More

In the Red (Why a Vehicle Overheats)

January 4, 2026

Heat is one thing that can damage a vehicle, especially if a problem isnt taken care of soon. Be on the lookout for signs that its getting too hot in some parts of your vehicle, starting with the most obvious one: the heat gauge/warning light on your instrument panel. When you see that heat gaug... More

Growing Old Together (Maintaining an Older Vehicle)

December 28, 2025

More and more of us are hanging on to our vehicles longer. A company by the name of HIS Markit recently released a report that shows the average age of light vehicles in the U.S. is now 11.8 years. Light vehicles are cars, SUVs (sport utility vehicles) and CUVs (compact utility vehicles). In C... More