CUCV gear oil (yes, I searched)

[TechnoWeenie]

So, here's the issue.

.mil spec says 75/90..

BUT....

Everything I've been reading about 14 bolt 4.56 rears suggests I should be running 75/140 instead.

Is it a supply issue? Ie the .mil said 75/90 was 'good enough' since it works on most of their vehicles?


Got an M1010, which is hauling a lot more weight than an M1008... So I wanna make sure I do this right...


I'm half thinking to go half 75/90 and half 75/140 to make a 75/115 ..lol

I've had experience with 'recommended fluids' not being the best, like Ford's modular motors spec'ing 5w20 instead of 5W30, they spec'd that to meet CAFE standards, not because it offered better protection, in fact, the 5W20 was shown to be worse than the 5w30..

 

[Gripy]

go for the 75/140. You'll be fine. I wouldn't worry about it too much.

 

[Recovry4x4]

I've never had an issue with the recommended 75W90 in any of my CUCVs and I'm in s FL. As a qualifier, yes I have a 1010.

 

[wheelspinner]

So in the space of two posts you get two different opinions. The inter web strikes again. Truth is they are probably both right.

 

[doghead]

Need I mention another option? Whale oil...

 

[Keith_J]

For the bearings, either is FINE. for the gears, as long as either has the correct extreme pressure additives, that also is fine.

I doubt whale oil, of any variety, meets the viscosity or extreme pressure additives.

 

[MarcusOReallyus]

I doubt whale oil, of any variety, meets the viscosity or extreme pressure additives.

I bet you're a barrel of laughs at a party.....

 

[doghead]

Best to withhold blind statements like that. Research BEFORE you post.

http://naldc.nal.usda.gov/naldc/download.xhtml?id=25253&content=PDF

Laboratory and simulated in-use lubricant tests
were performed on sulfurized jojoba oil and on reference
sulfurized sperm whale oil. Data from these
comprehensive tests indicated sulfurized jojoba oil
prepared from heat-treated filtered oil to be comparable
or superior to sulfurized sperm whale oil as an
extreme-pressure additive for motor oils, gear
lubricants, and automotive transmission fluids

 

[phil2968]

I sulfurized a whale once......., once. It didn't end well.

 

[TechnoWeenie]

Meh. Local auto shop had some full synthetic 85/120 for 5$ a GALLON.

If it doesn't matter that much, tell me why I shouldn't mix that with a gallon of synthetic 75/90 and dump it in front/rear diffs and call it a day?

 

[Westech]

You do understand that "synthetic" oil is just filtered oil from the ground? The stuff you buy at the store is NOT man made oil.
It is simply filtered oil to filter out the long strands to get a smaller strand base (less friction).
True synthetic oils cost about 1000$ a quart and are mainly used in jet turbine shaft bearings. I have acquired one quart in my oil collection and it sounds thinner then water when you shake the can.
You are able to mix gear oils synthetic and non with out issues.
As rear ends go at normal temps (0* and above) you can use any gear oil you can poor in there as long as it has extreme pressure additives. 75/140 80/90 ect.... Its not going to matter.
I use 80/90 in all my axles and manual transmissions (iron cases) (except M35 transmissions I use 40W non detergent motor oil)

 

[Iceman3005]

Most readers know that synthetic motor oils typically perform better than conventional motor oils in providing protection for your vehicle, but they might know why. What’s the real difference between synthetic and conventional oil? Pretty much everything.Conventional and synthetic oils begin in the ground. But that’s where the similarities end.
Synthetic oil is not only refined but also distilled, purified and broken down into its basic molecules. This process not only removes more impurities from the crude oil but also enables individual molecules in the oil to be tailored to the demands of modern engines, transmission, transfer cases, and differentials. These customized molecules provide higher levels of protection and performance than conventional oils. But the synthetic base oil is only half the story. The correct blend additives must go into the mix to create the oil.

 

[Recovry4x4]

Turbine oil at $1000 a quart (gulp)? Where were you 10 years ago when I got my M447C from Wayne Harris. There had to be 50 quarts of turbine oil in the trailer and yes, it felt watery to the shake. I added a few quarts a tank for years in the deuces. Perhaps that explains why I never had any injector or pump problems running 75% filtered WMO. Sadly that's $50,000 worth of fuel!

 

[TechnoWeenie]

There are different base stocks, some dino, some synthetic versions of dino, and some engineered synthetics that are built from the ground up, so to speak, synthetically.

I'm pretty aware of the science behind oil and lubricants, additive packages, etc just not to aware of the application limitations of them when it comes to gear vs engine lubrication.

 

[mkcoen]

Best to withhold blind statements like that. Research BEFORE you post.

http://naldc.nal.usda.gov/naldc/download.xhtml?id=25253&content=PDF

Wow, that's even from SW Research Institute (San Antonio, TX) but the conclusion is jojoba was better than the whale oil (nut is better than sperm). Personally I'd think regular crude oil distillates would be cheaper, but then I don't have the mad search skills doghead has so he may be able to find you a bargain.

 

[phil2968]

... but then I don't have the mad search skills doghead has ...

He learned it all from Clinto!

 

[Mainsail]

I'm guessing the mil-spec is related to the overall operating environments in which the CUCVs were expected to perform. The thinking may have been; it gets cold in Eastern Europe, well, at least until WWIII goes nuclear.

It doesn't get nearly that cold where you are. Run the heavier.