How Often Should I Change Front or Rear Differential Fluid?

It depends on your vehicle, driving conditions and differential fluid quality.

That’s a pretty vague answer, but it’s true.

If you drive your truck primarily on the highway in temperate conditions and rarely tow or haul, you likely don’t need to change front or rear differential fluid very often. But, if you tow a work trailer or haul supplies frequently and the temperature fluctuates as wildly as your health insurance premium, then you need to change the fluid more often. The only way to know the exact mileage interval is to check your owner’s manual or visit the dealership.

Bigger, faster, stronger

Why the varying fluid change intervals? Because severe operating conditions break down differential fluid more quickly and place greater stress on the gears and bearings, inviting wear.

The truck manufacturer’s ongoing arms race for the highest towing capacity has resulted in trucks that place far more stress on differentials than their predecessors. Meanwhile, differential fluid capacities have largely decreased or remained the same.

For example, compare a 1996 Ford F-250 Crew Cab to the 2017 version. Back in 1996, maximum towing capacity was 10,500 lbs. using a rear differential that held 3.75 quarts of gear lube. The 2017 model offers a 15,000-lb. towing capacity using a rear differential that holds 3.5 quarts of fluid.

Greater towing capacity, less gear lube

What does that mean for your truck? It means less fluid is responsible for guarding against increased heat and stress. In this environment, inferior lubricants can shear and permanently lose viscosity. Once sheared, the fluid film weakens, ruptures and allows metal-to-metal contact, eventually causing gear and bearing failure.

Increased temperatures are also a challenge. As temperatures climb, gear lubricants tend to lose viscosity, while extreme loads and pressures can break the lubricant film, causing increased metal-to-metal contact and heat. The increased friction and heat, in turn, cause the lubricant to lose further viscosity, which further increases friction and heat. Friction and heat continue to spiral upward, creating a vicious cycle known as thermal runaway that eventually leads to greatly increased wear and irreparable equipment damage.

That’s why you need to change differential fluid more often in severe operating conditions.

In our example above, Ford recommends changing differential fluid every 150,000 miles in normal service. But they drop the change interval significantly – to every 30,000 miles if using non-synthetic fluid – when towing frequently at wide-open throttle and driving at temps above 70ºF. Those restrictions apply to just about anyone who’s pulled a camper/boat/trailer anywhere in North America during most of the year.

Bottom line…

Use a high-quality synthetic gear lube to maximize your truck’s ability to tow and haul.

AMSOIL Severe Gear® Synthetic Gear Lube is specifically designed for severe service. It maintains viscosity better than other conventional and synthetic gear lubes despite rigorous use and it contains advanced anti-wear additives for further protection. It also costs less than most OEM-branded gear lubes.

FIND AMSOIL SYNTHETIC GEAR LUBE FOR MY TRUCK

05Jul 2019

AMSOIL Dirt Bike Crown Winner -Chase Sexton Wins Again Lindsay Premo|May 08, 2019 8:52 AM As I plopped down on the sofa with my second cup of coffee Sunday morning, I tuned the DVR to watch the Supercross finals from Vegas (#centraltimezoneprobs). I knew two things from watching heats and LCQs the night before: 1. […]

03Jul 2019
cetane boost mixed with lubricant

Injector’s Require It – Diesel Fuel Additive Only overlooked by those who don’t understand the critical fuel issues. Stock up and enjoy your diesel to the N’th degree!! New Diesel Injector Clean + Cetane Boost Available Now, Diesel Injector Clean + Cetane Boost (ADS) combines the superior detergency and improved lubricity of AMSOIL Diesel Injector […]

02Jul 2019

Weed Eater Won’t Start? Try This John Baker|Jun 19, 2019 9:28 AM No matter what you call it – weed eater, weed whacker, string trimmer – chances are at some point it won’t start. Few things are more annoying than destroying your shoulder trying to start the weed eater when there’s work to do. Fortunately, […]

01Jul 2019

How to Get Your Car Noticed at a Car Show (and Maybe Even Win an Award) Jamie Gibson|May 16, 2019 12:01 PM In November 1900, the Automobile Club of America sponsored the first “modern car show”, which took place in New York City. Referenced today as “The Grandmother of All Auto Shows”, it featured… 66 […]

01Jul 2019

MAXIMIZING THE SHELF LIFE OF AMSOIL PRODUCTS AMSOIL synthetic lubricants are designed to retain their original performance after a reasonable period of time in your storeroom. Proper storage ensures the freshest, most effective products possible. From fresh fruit to batteries, most consumable products have a shelf life. Synthetic lubricants are no different. AMSOIL engineers products […]

01Jul 2019

Team Hybrid Sets the Import Standard Jamie Gibson|May 01, 2019 1:39 PM It’s no small feat to organize a group of tuner enthusiasts and turn it into a well-respected car club. Never mind one that is capable of steady accolades, awards and reverence in a highly-competitive scene. That’s exactly what James Lin, Team Hybrid Founder […]