The stupid front driveshaft greasing....

[Longhorn1500]

What is the difference between a bearing and a joint?

In the case of a vehicle, the joint generally sees high load and slow motion, bearings lower load and fast motion. For wheel bearings, they also see high heat due to integral brakes, hence the development of lithium complex soaps and synthetic oils. First synthetic oil grease with clay thickener was used on jet fighter front brakes.

U-joint bearings see high load and slow motion like a chassis joint - the bearing doesn't spin much at shallow shaft angles, and all the power of the drivetrain goes through it - hence I like a medium weight lithium soap (doesn't have to be complexed for high temp, but most are anyway today) and oil, with moly for the high load. I get long life from both joints and drive bearings.

For front wheel bearings that are regreasable, I usually use a dedicated wheel bearing grease - lithium complex soap and synthetic oil without moly additive. For CV joints, these are usually polyurea soap greases these days because they are not maintained (sealed for life and not regreased). Polyurea is a synthetic soap that is extremely stable. Usually with synthetic oil.

Deere has suddenly become a disciple of polyurea grease everywhere, even chassis joints, because of increased water washout resistance compared to lithium complex soap. No thank you - polyurea was developed principally for extreme long life. You should regrease joints if you're gonna pressure wash them anyway. Polyurea very expensive, also. Further, polyurea is not mixible with lithium - the mixture turns to gum.

Interesting points, thank you!

 

[BossHogg]

What is the difference between a bearing and a joint?

In the context of what is being discussed, the difference is the pinned joint doesn't have 360-degree rotation and its movement is slow. Take the pin joint of the boom and stick or the bucket pin, limited back and forth movement and high-pressure points, where the pin slides within the joint, thus the reason for a moly-based lubricant. Bearings are supposed to roll, not slide on the moly film thus the reason moly is not recommended for bearings. This is what was explained to me many years ago. I am far from a lubricant specialist but I assumed my equipment service folks are more knowledgeable so I followed their advice and the equipment manual's recommendations.

I use Amsoil branded moly on all my pinned joints, it has the ability to form a surface skin that helps reduce water and dust/dirt penetration into the pin joints.