Thread: Oil Fed Wheel Bearings and CV's - The mixing of Diff Oil & CV Grease?

Originally Posted by AK83

While we're on the topic of that video, I was amazed to see how badly scored the axle seal face was due to the inner axle seal.

have to comment on the enjoyment factor too, of watching many thousands of dollars needing to be spent on a supposedly bulletproof Tojo.

Yes true... but we will never know exactly how much its costing him either + most of the parts have been donated free too...

and then there's the labour costs too!!

Originally Posted by Gippslander

Just a thought aren’t CV joints case hardened too ( I used to watch those videos but too much Toyota crap)
Just my opinion and I know the saying, I like Mr Foreman he’s more my style.

Gippy

The races are through hardened, and I'm pretty sure the balls are through hardened too.
Anyway, they are hard, that's why it's total BS.

Most CV greases us MoS2 as the solid lube additive for boundary layer lubrication.
MoS2 has also been used as the anti-chatter additive in LSD fluids, although there are better additives available.
MoS2 by and of itself is pretty much inert where we use it, whereas the sulphur/phosphorous compounds used as the EP additive package in the majority of diff oils chemically react with iron/steel asperites (the microscopic peaks on the gear surface) under heat heat and pressure to form a microscopic layer of material that is softer than the gear face, reducing wear.
This only happens when the hydrodynamic film of oil fails or is squeezed out, something that happens under load with a hypoid diff.
To have that chemical reaction were talking localised flash temps above 300*C, below that the compounds are inactive and at a guess the average gear oil temp will often be 100* or less.

The soaps used to retain the oil in the grease are pretty much inert too, usually a lithium, lithium complex or my preference in 4wd use, calcium sulfonate complex base.

Whoever made the original statement knows nothing of the chemistry of lubricants.