Duolec The Best Gear Oil.... A Challenge

jimdawg185

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So, for the most part lubricants have tangible and intangible benefits. Many of these benefits are attempted to be replicated via testing procedures. This is where engineers and tribologists try and recreate the in service conditions to attribute certain qualities to lubricants. The most important thing a lubricant does is prevent wear. They do this by inducing what is called a full fluid film lubrication regime. There are basically two types of friction, dry and fluid. Dry is bad and fluid is good, basically. When a lubricant is involved there are three basic lubrication regimes.... Boundary, Mixed Film, and hydrodynamic (full film) or in non friction roller bearings elastohydrodynamic. Boundary would be similar to what our engines encounter when they are started after sitting all night long. There is little to no lubricant between the opposing surfaces. It might be hard to imagine, but all of the surfaces involved in bearing and journal surfaces (or just about any other surface for that matter) are no where near smooth. Every machined surface has an RMS (root mean square) rating that determines the surface roughness. Imagine a mountain range, RMS basically measures the centerline average between the peaks and valleys. During boundary regimes these peaks from each surface (asperities) are fully engaged. In most lubricants there are types of antiwear and EP additives that assist in limiting the amount of wear during this regime. Soon after the the surfaces begin to move in relation to each other a film begins to build up between the asperities and starts to separate them. This state is called mixed film lubricating regime. During this regime, the highest peaks of the asperities still make contact. Then, we encounter soon after (hopefully) full fluid film or hydrodynamic. If you want more info on this, google the Stribeck-Hershey Curve. One thing that helps me picture what is happening here is a surf board. Different shapes, loads, and speeds all effect how well a surf board stays above water. Too slow, no good... to heavy, no good... not fast enough, no good.... These things all play in the details that determine the OEM viscosity requirements of a lubricant, among other things that effect vis at the wide span of temperatures that a lubricant will encounter.


Well, with that said....

Engine oils have their tests, trans fluids have their own. Then you have gear lubes. For the most part I will never put pre service lubricant tests above in importance to in service or post service. Lubrication Engineers always guarantees the performance of our lubricants post service, against any companies lubes of any cost. So I state the following with this in mind.


The main tests, other than your common viscosity tests, for gear lubes are Timken, 4 ball wear, and FZG.

For the most part, Timken is something that is important but can be a cheated in my mind. The test is difficult to manage because I can see some people putting the weight on fast, or slowly to effect the test. But, it is a standard test that most of the time can give you a good base of a lubricants ability to protect surfaces during boundary and mixed regimes. Our Timken on the Duolec gear lubes are really quite high, 75. Not too bad.

The next one in line would be the four ball wear test. This test is a little more difficult to cheat on, but not impossible. The test still depends on a person placing weights on a load bar, but I don't see it making as much difference as it could on Timken. On the FBWT you have the weld point, where there is a total loss of lubrication of any kind and the balls in the test completely fuse together. Then you have the load, and wear scare measurement. Great tests that attempt to recreate the boundary and or complete loss of lubrication properties. For the most part they are testing the EP additives. These additives are activated by heat and pressure.
Duolec has a 400 weld point with 77 kgf and a .33 wear scar. All very good test results where I have only seen one or two of our competitors beat us at, and those same lubricants will not beat us in any other test.

Then you have FZG. In my mind this is the best test for trying to recreate an in service recreation of all three regimes. The test involves a gearbox, so it is the only test that actually measures wear on gears, which is nice for a gear lube. The test can actually involve many many different types of wear (of which I will not go into in an attempt to keep this not a day long read) There are stages that the test involves. And basically in the big picture the more stages that the lubricant passes the better and less wear that a lubricant allows during service. Most high quality gear lubes are around a 12, which is pretty good. But, our Duolec is 14+... Ive heard 16. But in all reality 14 is the final acceptable stage. The other important thing to keep in mind is that FZG attempts to recreate all the lubrication regimes, not just EP and antiwear during boundary. Granted, the case for hydrodynamic is tough because the lack of lubricant involved. But its much closer than any of the other tests available.

So, the challenge.... is there another gear lubricant out there that makes it to 14+ in the FZG???? Where does your favorite gear lube make it too? We run our Duolec out to 400-500k miles in out OTR trucks with great success.

Please let me know what you find.... and please ask any questions that you might have.
 
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lincolnlocker

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amsoil ftmfw!






lol... might need some rear diff lube sent out here if i can find an address to send it too jim! 6.7 problems....

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jimdawg185

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Oh **** dude, I have some at my house too if your still in MI. I got you no matter where you are though bro...
Whats the story?

FYI, I haven't seen an Amsoil with over with over a 12... which is not bad at all, but a 14+ is stupid. Our 9920 that I use in my diffs right now is a 12+, so a 12 is not bad.
 

lincolnlocker

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Oh **** dude, I have some at my house too if your still in MI. I got you no matter where you are though bro...
Whats the story?

FYI, I haven't seen an Amsoil with over with over a 12... which is not bad at all, but a 14+ is stupid. Our 9920 that I use in my diffs right now is a 12+, so a 12 is not bad.
pinnion seal popped out of the housing at some point between the house and buffalo. guess there is a bunch of shavings in it.

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jimdawg185

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Man I'm sorry to hear that. I can ship to you anywhere you need. But in a spot you gotta go with whats available. Let me know if I can help!


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Magnum PD

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Jim I will be needing gear oil for my rear end sometime. With my differential having limited slip or clutches that need the limited slip oil, would your oil still need it or not.
 

lincolnlocker

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Man I'm sorry to hear that. I can ship to you anywhere you need. But in a spot you gotta go with whats available. Let me know if I can help!


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will do man.. as soon as a spot opens up at the driveline shop ill be asking them if i can have some diff oil shipped there.. then ill be calling.

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jimdawg185

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I've been running Schaffers full syn moly gear lube. How does this compare your duolec ?

They are both very good gear lubes. The Duolec does go two stages past everything else out there. There was one Schaffers that had a stage 13. But I can't seem to find much info on it. The Duolec will climb and stay on the gears much better than anything else out there as well. Imagine the Lucas gear box demo on steroids.
 

jimdawg185

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Jim I will be needing gear oil for my rear end sometime. With my differential having limited slip or clutches that need the limited slip oil, would your oil still need it or not.

Our multi grade 704/703 and 9919/9920 do have the modifier in them the Duolec does not. The 9920 is what I run and it works great. But it is on par with all the other FZG tests out there. The only advantage to 9920 and 9919 is the lower pour point. But unless your are way below zero there is no real advantage. I will be switching over to 1606 Duolec when I put my lockers in.
One of my customers is Venom Motorsports in Grand Rapids MI. ARB has warned them to not use synthetics with their lockers. This was our solution.

I will say that the 9920 and 9919 will last really long. We run it to 750000 miles in our OTR big rigs. Duolec and 703/704 we run out to 400k.

Duolec will separate from water like no other as well. Its stupid how good this is at it.
 

lincolnlocker

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Our multi grade 704/703 and 9919/9920 do have the modifier in them the Duolec does not. The 9920 is what I run and it works great. But it is on par with all the other FZG tests out there. The only advantage to 9920 and 9919 is the lower pour point. But unless your are way below zero there is no real advantage. I will be switching over to 1606 Duolec when I put my lockers in.
One of my customers is Venom Motorsports in Grand Rapids MI. ARB has warned them to not use synthetics with their lockers. This was our solution.

I will say that the 9920 and 9919 will last really long. We run it to 750000 miles in our OTR big rigs. Duolec and 703/704 we run out to 400k.

Duolec will separate from water like no other as well. Its stupid how good this is at it.
so whats supposed to be in a stock e-locker 6.7 rear end?

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jimdawg185

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so whats supposed to be in a stock e-locker 6.7 rear end?

live life full throttle

All the rear end options on the 6.7's (and all of our other trucks) require a GL5. So all of those I mentioned will work.

If you drove a thousand miles a week like me, I would go with 9920. It will basically last 100k without breaking a sweat.

Otherwise I would just stick with the 704. It cost half as much and will spank anything else out there.

I would go with the duolec if you had heavy mods to the truck and sled pulled with it.
 

lincolnlocker

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All the rear end options on the 6.7's (and all of our other trucks) require a GL5. So all of those I mentioned will work.

If you drove a thousand miles a week like me, I would go with 9920. It will basically last 100k without breaking a sweat.

Otherwise I would just stick with the 704. It cost half as much and will spank anything else out there.

I would go with the duolec if you had heavy mods to the truck and sled pulled with it.
whats the service interval on the 704.. are they all a 75-140 oil?

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jimdawg185

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The service interval for either lubricant is actually 150k according to Fords website. But I would not take anything out over 60k except the 9920 in my mind.
The 704 is 196$ a bucket, the 9920 is 450$ a bucket....
I hope I looked that up wrong, because 150k sounds way too long to me.
 

jimdawg185

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9920 is 75-140, 704 is 85-140 and 1606 duolec is a straight 140 but the VI is high enough to give it a good low temp flow.
 

MT_Diesel

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Jim-
I'm needing to do F&R gear oil change in the next few months. My 2008 F350 with factory limited slip rear probably puts down 650-700 hp but will live an easy life (I just got it). 10-15k per year and no hard use. I live in Montana so we get maybe 2 weeks of below 0 temps per year otherwise it's just below freezing. I may do a little offroading but nothing too serious, but I'd worry about water contamination probably before exceeding the life of the oil.

Would you still recommend the 704?

Planning to run your engine oil too when I do my first oil change. I'm waiting with bated breath for the PSA member deal you said would be up in a few hours in your thank you thread. :) Just giving you a hard time. Thanks!
Ryan
 
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jimdawg185

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I would say the 704 is the way to go. I will have the PSA promo worked out soon. We were doing a change over to my turbine oil in a medium sized steam turbine last week and when we took it apart to check out a sensor we discovered that the thrust bearing was destroyed. So Im working on root cause stuff for a competitors lubricant right now.
 

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