Corn Head Grease vs Lithium Grease: Why Regular Grease May Not Work

A lot of people look at a tube of grease and think, “Grease is grease.” That is where problems begin.

When comparing corn head grease vs lithium grease, the difference is not just branding. These products can behave very differently inside a gearbox. One may flow and protect gears. The other may sit in one place and leave parts under-lubricated.

So, before you pump regular lithium grease into a gearbox, it is worth understanding the difference.

What Is Corn Head Grease?

Corn head grease is a soft, semi-fluid grease used mainly in corn head gear cases and other slow-speed gearboxes. John Deere’s AN102562 corn head grease is listed as NLGI grade 0, with a green color and compliance with John Deere standards JDMJ13A5, J13E6, and J25A.

That NLGI 0 rating is important. It tells you the grease is soft enough to move inside a gear case.

What Is Lithium Grease?

Lithium grease is one of the most common greases used around tractors, trucks, trailers, mowers, and farm equipment. It is often used on pins, bushings, bearings, universal joints, and general grease fittings.

But most common lithium grease is NLGI 2, which is much thicker than corn head grease. Tractor Supply’s automotive grease catalog, for example, includes several No. 2 lithium or lithium-complex grease products for general lubrication. tractorsupply.com

That thickness is useful for grease fittings. It is not always useful inside a gearbox.

Corn Head Grease vs Lithium Grease: Main Difference

The main difference is flow.

A gearbox needs lubricant to reach the gears. If you use thick lithium grease in a gearbox that needs soft grease, the gears may push the grease aside. Then the grease stays stuck to the case while the gear teeth run with poor lubrication.

That is why regular grease may not work.

Why Regular Lithium Grease Can Fail in Gearboxes

A slow-speed gearbox needs backflow. That means the lubricant must move back into the gear contact area after it is pushed away.

Corn head grease can do this better than standard No. 2 grease because it is softer. It can slump, flow slowly, and return to the gears.

Regular lithium grease may not. It can form channels and leave gear teeth exposed.

This is one reason D-A Lubricant describes its corn head grease as having NLGI #0 grade, leakage resistance, EP/anti-wear protection, anti-leak thixotropic action, and water washout resistance.

Is Lithium Grease Ever a Corn Head Grease Substitute?

Usually, standard No. 2 lithium grease is not a good corn head grease substitute for a corn head gearbox. It is simply too thick for many enclosed gear cases that require semi-fluid grease.

However, some low-consistency greases may use lithium thickener. For example, certain 00 greases use lithium thickener, but that does not make them the same as common No. 2 lithium chassis grease.

So, do not judge by “lithium” alone. Judge by:

• NLGI grade

• equipment application

• EP rating

• water resistance

• OEM recommendation

• gearbox speed and design

When Corn Head Grease Is the Better Choice

Use corn head grease when:

• the machine calls for corn head grease

• the gearbox requires NLGI 0

• you are servicing corn head row-unit gear cases

• gear oil leaks from worn seals

• the gearbox is slow-moving

• you need soft grease that can flow

When Lithium Grease Is the Better Choice

Use lithium grease when:

• the manual calls for general-purpose grease

• you are greasing pins or bushings

• you are lubricating chassis fittings

• you are servicing bearings that call for No. 2 grease

• the grease point is not an enclosed gearbox needing semi-fluid flow

Regular lithium grease is not bad. It is just made for a different job.

What Happens If You Use the Wrong Grease?

Using the wrong grease can cause:

• dry gear contact

• overheating

• gear wear

• bearing failure

• poor cold-weather flow

• leakage

• grease separation

• expensive gearbox repair

The worst part? The gearbox may look full. You may open the plug and see grease inside, but that does not mean the gears are properly lubricated.

The difference between corn head grease vs lithium grease comes down to flow and application. Corn head grease is usually softer and better suited for slow-speed gearboxes. Regular lithium grease is usually thicker and better suited for grease fittings, pins, bushings, and bearings.

If the manual calls for corn head grease, do not replace it with regular lithium grease just because you already have a tube in the shop. The right grease is cheaper than a damaged gearbox.