Grease: Waterproof or Not?

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Getting ready to place an Amsoil order and noticed they have two grease options: standard synthetic ans waterproof

They're both NGLI #2 and price delta is nominal. I've read that the waterproof greases break down more quickly and may require more frequent maintenance. This isn't a concern as I tend to over-maintain anyway. Any other comments or suggestions?

Also, how many tubes are you using on a typical maintenance cycle?
 
I think waterproof grease uses something other than lithium soaps to thicken the oil into grease. I've heard some waterproof greases are not compatible with lithium-based grease.
 
I think waterproof grease uses something other than lithium soaps to thicken the oil into grease. I've heard some waterproof greases are not compatible with lithium-based grease.

The Amsoil link shows that their brand is a lithium grease. However, I've not seen a bunch of replies touting the benefits of waterproof so I'm just going to go with the standard.
 
FWIW: For the past 4-years or so I've been using their (Amsoil) waterproof grease on my front hub bearings. And their #1 non-waterproof on my u-joints and the CV spindle needle bearing. No issues.

FWIW #2: The seals apart of the front hubs are very, very well designed. Even after repeated water crossings, extended repack intervals, water penetration is nil. So I'm not sure there is any real benefit to running the thicker waterproof grease anyway for this application...
 
I wouldn't want moly on roller/needle bearings.
 
So what exactly is the difference between moly and multi purpose greases? Also, what is all this NLGI rating stuff? Sorry if this is a stupid question but I was hoping for a quick and dirty run down without reading a thesis paper.
 
Very simply: Moly (Molybdenum disulfide) is similar to graphite in the sense it is added/compounded to grease for its friction reducing benefit as well as being higher temperature tolerant. Moly fortified grease will reduce the friction between sliding metal surfaces among other good properties. Think of moly as microscopic ball bearings...not really but you get the picture. Moly fortified grease works really well on our drive shaft/yoke splines and interface surfaces.

NLGI (National Lubricating Grease Institute) is a non-profit organization that has developed standards for lubricating greases. The # correlates to its ability to flow and/or viscosity for lack of a better term. So think of #1 NLGI grease as less thick or viscous than #2 and so on.

#2 is too thick for u-joints IMO. Whereas wheel bearings might benefit from the thicker 'viscosity' of #2 mainly for its pressure resistance.

Both of these subjects are near thesis material ;) And this is my layperson understanding of the subject.
 
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when rebuilding knuckles on FJ60...it calls for moly grease...used the amsoil red grease and worked great.

no matter how good a grease is...gotta use proper stuff for proper application...just like oils and other things.

good discussion though as the synthetic general purpose greases are good for 90% of applications I found.
 

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