Don't Take Grease for Granted on Heavy-Duty Trucks

Grease has been called the "Rodney Dangerfield of lubricants." The late comedian was often known to lament, "I just don't get no respect." Likewise, grease is often an afterthought when it comes to heavy-duty truck maintenance.

Even Kirk Altrichter, vice president of maintenance at Gordon Trucking, a man who has a six-page slide presentation for technicians on the proper way to grease fifth wheels, admits "it's hard to listen to an engineer talk about grease for 45 minutes."

Nevertheless, Altrichter does pay close attention to his grease and greasing procedures. He uses three different types of grease: one for chassis items such as slack adjusters and ball joints; a synthetic grease for the differential and wheel ends; and another grease for fifth wheel top plates.

His team has spent six or seven years experimenting with different greases to see what works best for the fifth wheel top plate, one of the toughest areas to keep properly lubed. And technicians for the Pacific, Wash.-based company, which operates about 1,600 power units, go through extensive maintenance training, including proper greasing procedures.

There are industry trends at work today that make it more important than ever to give your grease some respect.

Extending Heavy-Duty Truck Oil Change Intervals

One is extended oil drain intervals. Some fleets today are up to 30,000-mile engine oil change intervals, says Mark Betner, Citgo heavy-duty lubricants manager. If fleets do their "dry" maintenance at the halfway point, that means they're greasing at 15,000 miles.

"That's not outside the range of a decent grease today," Betner says. "But some have eliminated that dry maintenance or moved it out beyond 15,000, and that's where you start to get into trouble."

Corrosive De-Icers

Another trend that affects grease is the use of more corrosive de-icers on highways. If the grease gives out in your U-joints, for example, not only can you get water inside, but that water can be carrying magnesium chloride or calcium chloride. The resulting corrosion can literally wipe out the needle bearings, Betner says.

"I've found that guys who say they're not having [lubrication] problems are just accepting the problems as business as usual," Betner says.

Fifth wheel repair or replacement, having to readjust the jaws of a fifth wheel every 100,000 miles, kingpin and U-joint replacement — these are all possible signs that your grease isn't working as well as it should, he says.

Understanding Grease Basics

In order to think about grease, it helps to know a little bit about how it's made.

The main ingredient in grease is oil. Just as with engine oil, there are different types of base stocks, or it may be a synthetic oil.

Next there's the thickener, which in basically a type of soap, explains Dan Dotson, a lab manager for Valvoline in Lexington, Ky. Lithium and lithium complex are the most common, he says, but others, such as sodium, calcium, and barium, each have different performance aspects.

Finally, there are the additives, which handle tasks such as rust protection and resisting water washout.

"Additives make a grease unique," Dotson says.

So there's a lot more that goes into grease than just slippery stuff.

"There is a lot of work [being done] around optimizing grease formulations to provide increased load protection, water spray-off performance, and longer performance life to reduce grease intervals and provide extended protection performance," says Leonard Badal, commercial sector manager for Chevron Lubricant Marketing.

"In some of these formulations there is also focus on utilizing the benefits of premium base oils to provide additional performance capabilities of the greases."

Chevron will be introducing several new greases to address extended maintenance intervals this year.

Choosing the Right Grease for Your Truck

The first thing to look at in choosing a grease is the owner's manual. The maker of the equipment will have specific requirements for lubrication.

One of the key requirements will be the NLGI classification for grease consistency. The National Lubricating Grease Institute has a system of automotive service grease classifications, established jointly with the Society of Automotive Engineers and the ASTM standards organization.

This NLGI system ranks greases from 000 ("triple-aught"), which is the consistency of cooking oil, all the way up to 6, which is very hard brick grease, the consistency of cheddar cheese.

For most trucking applications, you'll use NLGI No. 1 or No. 2. NLGI 1 is often used in cold-weather applications, especially where maintenance may not be done in a heated shop.

"A lot of people try to use No. 2 grease in some winter applications where they ought to be using No. 1 or aught (zero) grade grease because of the consistency of the grease," says Chuck Hamilton, technical service specialist for CHS, which makes Cenex brand lubricants.

"If they want to get the grease pumped out of the cartridge at 20 below, they ought be using a No. 1 grease, because the pumpability is a lot better."

Indeed, pumpability of grease can be a "bugaboo," Betner says.

"Your technicians will complain and you'll lose faith in the grease because it didn't pump well. There are products, especially synthetic greases, that will pump beautifully and you'll be happy with your grease."

Automatic lubrication systems might get down into the aught grades, such as 0 or 00.

NLGI also classifies greases with the terms LB for chassis and GC for wheel bearing. If you want a grease that can be used for both, look for a GC-LB designation.

There's More to Grease Than Consistency

There's more to a grease than how thick it is. Beyond the requirements of the equipment manufacturer, there may be other performance characteristics you want to consider for your particular application.

"A lot of times people judge heavy-duty grease by how tacky it is, and that's not always the concern," says Hamilton.

People often look for grease that produces a long strand when stretched between the thumb and forefinger. But that doesn't necessarily mean it's a quality grease. In fact, notes the Technology and Maintenance Council of the American Trucking Associations, too much tackiness is a detriment to fuel economy. The grease offers too much resistance to movement.

"You want to look at the dropping point and what grease consistency you want in that operation and for the temperatures," Hamilton says. (Dropping point is the point at which the grease turns to a liquid, usually due to heat. You want a higher dropping point for higher-heat operations.)

If you operate in areas where corrosive de-icers are an issue, you'll want a grease that resists water wash-out. There's an ASTM test that measures how well a grease performs when exposed to synthetic sea water, Betner says.

Other test results to ask your supplier about, he says, include temperature range, water washout, and 4-Ball Weld.

To help evaluate a grease, get your hands on the product information sheet, Dotson says, which will offer more information than you would get just from a label. Many grease manufacturers also have these sheets and other detailed information available on their websites.

Should You Use Synthetic Grease in Your Truck?

Synthetic greases offer advantages in some applications, but they do have a higher up-front price.

"If you use a synthetic base, that improves long-term oxidation stability, but that's a cost," says Valvoline's Dotson.

Excellent performance at both high and low temperatures is the primary benefit to using synthetic grease, often translating into longer life for components.

"You've really got to look at the componentry and see if there's a benefit," says Dan Arcy, Shell OEM technical manager. For instance, he says, if you have an automatic lubrication system on the truck, there are some benefits because of better flow at cold temperatures.

"You are seeing more and more of the full synthetics coming into play," says CHS's Hamilton. He notes that in addition to pumpability in cold-weather applications, synthetic or semi-synthetic greases can help fleets meet needs for more extended maintenance intervals.

Chevron's Badal cautions that just because a grease is synthetci doesn't necessarily mean it will automatically perform "better."

"Grease thickener technology can provide performance advantages in premium greases that may not have synthetic base oils," he explains.

"As with any application, it's important for the operator to understand their application and conditions and determine if there is a benefit that the synthetic grese is providing that offsets its much higher cost over a 'premium' based grease option."

Be careful if you're switching greases to watch for compatibility issues. The most common thickener used in trucking grease is lithium or lithium complex, but it may not be compatible with other types of thickeners. The most common result is substantial softening, according to Hamilton. Lithium grease, however, sometimes hardens.

Even if the thickeners are generally compatible, two greases may still contain clashing base oil or additive formulations.

How Many Greases Do You Need in the Shop?

There is a lot of focus on a "one-grease" application for all parts of the truck, including wheel bearings, chassis, kingpins and fifth wheels, with extended service performance in various climates and operating conditions, says Chevron's Badal.

"For most on-road and off-road trucks, typically a customer can utliize one or two greases to cover all greasing operations," he says. "However, depending on the type of operation, maintenance program, and age of the equipment, operators should look to utilize premium greases to help reduce operating costs."

One area where you may want to consider a different grease than you use for chassis lube is the fifth wheel top plate. Some companies offer special greases specifically designed for the tough conditions faced in this area. Because of their exposure to the elements, fifth wheels experience a lot of water spray — water than can contain a lot of sale and chemical de-icers in the winter. So fifth wheel greases are designed to better resist water wash-out.

"From a fifth wheel perspective, which is generally the hardest place to keep grease, [we look at] how much grit it's going to pick up and retain, how well does it lubricate, how well does it stay on the fifth wheel," says Altrichter. "It's been a matter of trial and error. We've tried six or seven greases in the past six or seven years."

The fleet has currently settled on an "extreme pressure" grease with high adhesive properties, even in wet, muddy and dusty conditions.

Not everyone is as thorough in their grease selection as Altrichter. For many companies, grease is purchased based almost solely on up-front costs. But that approach may be short-sighted.

The amount and cost of grease used on a truck is relatively small compared to the cost of labor, replacement components, and potential downtime that may result from using a cheaper, lower-quality grease, says Badal.

"This is an area that most operators can actually spend money on a premium grease product and reap potential significant cost savings in operations/maintenance."