Diff oil

[JTGuy]

Torco RGO 85-140 all the way. It's a Dino oil used by Currie.

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[HVYMETL]

My vote is 75w-90... I also change every 2 years. I live in Phoenix so not often crossing water. If I did a lot of mud or water crossing it would be more often. Full Synthetic is my choice.

 

[HueCity0846]

Just a note on full syn, it runs hotter than dyno.

 

[ShadowsPapa]

Just a note on full syn, it runs hotter than dyno.

Not modern synthetics. The film strength tends to keep the gear faces cooler thus the lube runs cooler.

Digging deeper, even Currie was wrong.

 

[Hootbro]

Not modern synthetics. The film strength tends to keep the gear faces cooler thus the lube runs cooler.

Digging deeper, even Currie was wrong.

Where are those image quotes from?

 

[ShadowsPapa]

Where are those image quotes from?

BITOG.
There is quite a discussion there and one guy threw in the math and science.
Seems some there take the actual measurements over repeated beliefs?

 

[Hootbro]

BITOG.
There is quite a discussion there and one guy threw in the math and science.
Seems some there take the actual measurements over repeated beliefs?

Thanks.

From what I read from Currie, they do not make the blanket claim that their recommendation of 85W-140 conventional will make the oil itself run cooler, just that it absorbs the gear surface heat and the gear surface will run cooler.

Currie also does not make the recommendation or infer it past just their axle and gear sets which they base most of it on the Ford 9" high offset gear for better shock loading protection which our DANA 44 Advantek are not high offset.

https://www.currie4x4.com/why-run-conventional-gear-oil

 

[ShadowsPapa]

Thanks.

From what I read from Currie, they do not make the blanket claim that their recommendation of 85W-140 conventional will make the oil itself run cooler, just that it absorbs the gear surface heat and the gear surface will run cooler.

Currie also does not make the recommendation or infer it past just their axle and gear sets which they base most of it on the Ford 9" high offset gear for better shock loading protection which our DANA 44 Advantek are not high offset.

https://www.currie4x4.com/why-run-conventional-gear-oil

One place I found when digging into this a couple of years ago when people here were poo-pooing synthetics due to the heat suggested that places like that (Currie)are using old info, not current tests.

If the film of synthetic fluid is better at reducing FRICTION, there will be less heat to deal with to begin with. People leave that part out - reduce friction, you reduce heat, regardless of the fluids ability to transfer heat. Prevent the metal-to-metal contact through film strength, no extra heat, no need to remove extra heat. Prevent it, don't deal with it after the fact.

People keep loving to quote that Currie bit all over the place, even in engine discussions, but from my research, there's something fishy about their testing or results, or perhaps the very lube they were using was inferior (some say RP doesn't do nearly as good a job as Amsoil or other brands at preventing hot gears)

Odd how other makers say run synthetic, and the science supports it (less friction means less heat generated)

Maybe Currie was using some specific brand that just was crappy from the word go.

 

[Hootbro]

Maybe Currie was using some specific brand that just was crappy from the word go.

What I heard/read second hand was that their warranty claims went down significantly calling out conventional vs. synthetic during the 500 mile break in.

 

[ShadowsPapa]

What I heard/read second hand was that their warranty claims went down significantly calling out conventional vs. synthetic during the 500 mile break in.

Maybe the issue is really their gears?
Other companies specify to use synthetic, they seem to be the outlier - unless maybe you know of others?? (no one person can see every single bird in the sky)

 

[Hootbro]

Maybe the issue is really their gears?
Other companies specify to use synthetic, they seem to be the outlier

Just my 2 cents, I think Currie has their reasons, just their reasons are not conveyed well to the general public and the internet masses take things out of context and plug in their own theories to fill the holes.

Mentioned before DANA burnishes their OEM gear sets to negate break in oil changes when most others do not. Could be as simple as that.

I tend to error on the side they know what they are doing and what is best for them. They make no claims outside of what they sell and if the outside masses what to extrapolate any meaning to it for their OEM or other brand gears, that is on them.

 

[Supazuk]

Interesting. I wonder what about the ARB lockers makes them recommend 75W140. It is usually the bearings & gears that dictate the recommended fluid.

TORQ lockers recommends 75W140 also ... as do all aftermarket gears kinda starting to wonder

 

[CrazyCooter]

I can tell you my warranty claims with burned gears (improper break in/never changed the break in oil) went to ZERO after I started shipping every new gear job with Amsoil Severe Gear 75W140 about 10 years ago. Cheap insurance!

I also noted the high diff 195° and trans 208° oil temps on my trip home from SoCal with my newly acquired unloaded Peterbilt during 100° ambient temps. I swapped everything over to Amsoil as I prepared it for my RV towing use. I consistently saw temps 30-40° lower and NEVER as high as the first ride home even while loaded to 56,000lb even in higher ambient temps.

Disclaimer: YMMV

 

[ShadowsPapa]

Mentioned before DANA burnishes their OEM gear sets to negate break in oil changes when most others do not. Could be as simple as that.

Dana does, but other after-market gear makers apparently do not, given the rather detailed break-in periods and steps they insist you follow. To me that says - not burnished from the gear maker, cut and shipped.

Is Currie the only after-market, third party supplier that says not to use synthetic (while other information says it's superior in preventing friction and wear)?

MAYBE the synthetic prevents proper break-in? Too good at reducing friction?
Hmmm, I wonder........ what if you did the break-in with what they recommend, then 1,000 miles down the road, switch to synthetic? If that worked, it would seem to support the idea that synthetic prevents break-in and burnishing of their gears.

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