It can mean even more work, unless you use AMSOIL Severe Gear® easy-pack.


Anything described as “maintenance-free” gets our attention. When it’s time to upgrade your house, I bet you’re more likely to opt for the maintenance-free siding than the brand that requires fresh paint every few years. Time to upgrade the contents of your closet? I suspect you’re more likely to buy the wrinkle-free pants or shirt than the traditional clothes that require you to take out the iron and ironing board to look your best.

No one wants to perform unnecessary maintenance. We value products that promise to restore our most valuable resource: time.

That idea has influenced how many original equipment manufacturers (OEMs) design their vehicles. We’re seeing more vehicles roll off assembly lines with “filled-for-life” transmissions that (allegedly) don’t require motorists to spend a second of their time or penny of their money on a transmission fluid change during the vehicle’s lifetime. All things being equal, what casual motorist isn’t going to opt for the vehicle with a transmission that eliminates the hassle of dropping $150 or so on a transmission flush and wasting time at the dealership or repair shop?

The dirty little secret, of course, is that “filled-for-life” simply means “filled for the life of the warranty.” If the transmission fails after you’ve eclipsed the vehicle warranty period, what do you suppose the dealership is going to do for you? Slide a bill for $2,000 or so across the counter, that’s what.

It’s a good idea to change fluid in a “filled-for-life” transmission at least once during the vehicle’s lifetime, particularly if you tow or haul. Heat breaks down transmission fluid and causes sludge to form, which can clog the narrow fluid passages in the transmission’s valve body. Worn, dirty fluid also contributes to clutch wear and glazing, which you experience as elongated or jerky shifts. “Filled-for-life” transmissions contain drain and fill plugs, so changing the fluid is possible.

“Filled-for-life” differentials are also popular. The 2016 Ford* Super Duty 250, for example, is considered “filled for life.” However, the owner’s manual instructs you to change the fluid every 50,000 miles in “severe” conditions and anytime the differential is submerged in water. Did you hear that, anglers? The 2017 Toyota* Tundra* likewise features a “filled-for-life” differential. But Toyota tells you to change fluid every 15,000 miles if towing.

Don’t think older vehicles are immune. A 1996 Chevy* Suburban* has a “filled-for-life” differential. Again, though, GM recommends 15,000-mile fluid changes in “severe” service.

As with a “filled-for-life” transmission, never changing the gear lube in your differential is a bad idea. Today’s vehicles make more power and torque than their predecessors, yet the gears and bearings that put all that power to the ground are largely unchanged. Adding to the challenge, many automakers have reduced the amount of gear lube in the differential to reduce energy lost to friction and boost fuel economy. Lower-viscosity fluids are also gaining popularity in an effort to increase fuel economy.

This scenario creates the perfect opportunity for extreme heat to wreak havoc on your differential. Towing and hauling increase friction, which in turn increases heat. Extreme heat causes the gear lube to thin, reducing the effectiveness with which it keeps gear teeth separated and prevents wear. Thinner gear lube further increases friction, which causes heat to increase in a vicious cycle known as “thermal runaway.”

The solution to thermal runaway certainly is not to ignore your differential and never change the gear lube, despite what the owner’s manual might suggest. Most truck and SUV owners automatically fall under the “severe” driving designation due to towing and hauling, so they require differential service. Even if your driving habits don’t fall under the “severe” designation, it’s still a good idea to service the differential at least once during the vehicle’s lifetime. Again, “filled-for-life” means “filled for the life of the warranty.” If you burn up a bearing or chip the gear teeth in your “filled-for-life” differential once the warranty period has ended, don’t think for a second that the dealership is going to resolve the problem without charging you a ton of money.

Anyone who’s changed gear lube in their pickup or SUV knows the challenges: a tough-to-reach fill hole, gear lube spilled everywhere and bloody knuckles. Our new SEVERE GEAR easy-pack offers the perfect solution. Compared to rigid conical bottles that waste a quarter of the gear lube or more, our easy-pack offers the dexterity to maneuver around vehicle components and the flexibility to install nearly every drop of gear lube. It eases the process of changing gear lube, saving you time and hassle.

AMSOIL SEVERE GEAR Synthetic Gear Lube. It saves you maintenance and money in the long run. And now it’s easier to use than ever.

Use the AMSOIL Product Guide to determine the correct products for your vehicles and equipment.

SLS Note: My mechanic has a customer that had a new pickup truck. At around 30,000 miles he lost the differential. Replaced under warranty, the customer insisted on using the factory fluid. Had to replace it again at between 60,000 & 70,000 miles, no warranty coverage. Replaced and used AMSOIL Severe Gear this time. Vehicle now has 170,000+ and still going strong. No differential problems.

This article is from the September 2018 issue of the AMSOIL Dealer Magazine.

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