Warning: oil thread

The Evil Twin

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I know there are threads with folks asking about gear oil vs. SUDT² and axle lube.
Picked up the goods to do the 50 hour service in my L today. Told the parts dude what I was doing. He pulled it all from the shelf and brought it to the counter. I asked about the 15w40 oil. He said that it's what is generally recommended for our climate. We rarely see below 10°f and it fits the spec from K (14°f min for the 15w). Also, for the front axle, he said the gear oil was preferred over the SUTD² for those that use 4wd a lot in our area.
Just passing on the advice from an established Mid-Atlantic dealer.
 
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The Evil Twin

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Oh yeah- if you haven't changed your front axle lube at 50 hrs.....do it. I know that color is not an indication of oil health. Never the less, I'd was dark as night compared to the fresh SUTD ² that was fresh out of the bottle. Assuming that was what came in it.
 

rjcorazza

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I prefer gear oil in the front axle also. I use my tractor a lot in the winter for plowing (except this year!) so I prefer a 5w40 engine oil.
 
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DustyRusty

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I prefer the Super UDT for the front axle because it lubricates better when the temperatures are in the low teens and I am out snow-blowing or plowing in 4-wheel drive. Everyone has their own choice of fluids and there is no right or wrong, just preferences. To get an idea of what I am talking about, put a bottle of 80-90 gear oil in the freezer for a day, then take it out and see how well it pours out of the bottle. Then do the same with a bottle of Super UDT. Let me know your results.
 
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TheOldHokie

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I prefer the Super UDT for the front axle because it lubricates better when the temperatures are in the low teens and I am out snow-blowing or plowing in 4-wheel drive. Everyone has their own choice of fluids and there is no right or wrong, just preferences. To get an idea of what I am talking about, put a bottle of 80-90 gear oil in the freezer for a day, then take it out and see how well it pours out of the bottle. Then do the same with a bottle of Super UDT. Let me know your results.
Thats the basic idea. The LRI channel point test (FTM-3456) s the actual test procedure used to quantify this performance. It determines the temperature at which the rotating gear teeth cause the oil to form a channel that does not close up behind them to recoat the trailing teeth. That results in loss of oil film and boundary lubrication conditions that accelerates wear.

Channel point temperature is a basic requirement for the API gear oil service category certifications and all GL4 and GL5 lubricants have to pass the same test. Off the top of my head I dont know the pass/fail temperature but I can look it up if you would like to know.

Dan
 
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The Evil Twin

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I prefer the Super UDT for the front axle because it lubricates better when the temperatures are in the low teens and I am out snow-blowing or plowing in 4-wheel drive. Everyone has their own choice of fluids and there is no right or wrong, just preferences. To get an idea of what I am talking about, put a bottle of 80-90 gear oil in the freezer for a day, then take it out and see how well it pours out of the bottle. Then do the same with a bottle of Super UDT. Let me know your results.
The pour point for both is in the mid -40s (synthetic EP 80w90). Channel point for gear lube is in the upper -30s. Plow truck differentials don't seem to suffer with the gear oil. Admittedly, those are typically 75-90 which gets you into the low -50s for a pour point.
It is very convenient to use 1 oil for both trans and axle, though. I have a variety of partial bottles of all sorts of stuff in the shop.
 
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The Evil Twin

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I dont have an actual measured channel point temperature for SUDT2. Do you?

Dan
Hmm...went back through my browser history a little. Not honestly sure where I got it. Will remove that part so as not to confuse anyone. Given the other specs, I can't imagine it would be significantly lower than the spiral bevel gear lube.
 

TheOldHokie

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Hmm...went back through my browser history a little. Not honestly sure where I got it. Will remove that part so as not to confuse anyone. Given the other specs, I can't imagine it would be significantly lower than the spiral bevel gear lube.
I can only speculate.

Conventional 80W90 gear lube has a KV100 around 14 cSt, a viscosity index around 95 and a typical channel point <-30C

Synthetic 75W90 gear lube has a KV100 around 14 cSt, a viscosity index around 190 and a typical channel point <-50C

SUDT2 has a KV100 around 8 cSt and a viscosity index approaching 200.....
 
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kubotafreak

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In layman speak how far down your driveway at -40 until the gear oil has adequate lubrication properties? I cant imagine it is long probably 10 feet, maybe less. Truck differentials seem to do just fine with this same concept.
The long term use in high load situations should worry you much more than static low temp pour properties. You don't see people using an 8centistroke fluid in their vehicle differentials up north because it flows better. I can assure you my tractor front axle works much harder than my truck differential. A gear setup cares little about static cold flow properties than say your lower end in an engine. Nothing is translating, just rotating. Gear trains use the viscous properties of the fluid to lubricate sufficiently. The fluid is not pumped like in an engine. It survives based on windage. More viscous, more windage. When you are out in the freezing weather with the tractor moving, the front axle is nowhere close to ambient.

The true test is pull gear oil out of a front axle from a tractor up north, and conversely drain udt. You will be easily sold on what is carried out with the fluid.
 
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TheOldHokie

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In layman speak how far down your driveway at -40 until the gear oil has adequate lubrication properties? I cant imagine it is long probably 10 feet, maybe less. Truck differentials seem to do just fine too.
The long term use in high load situations would worry me much more than static low temp pour properties. You don't see people using an 8centistroke fluid in their vehicle differentials up north because it flows better. I can assure you my tractor front axle works much harder than my truck differential. A gear setup cares little about static cold flow properties than say your lower end in an engine. Nothing is translating, just rotating. Gear trains use the viscous properties of the fluid to lubricate sufficiently. The fluid is not pumped like in an engine.
When you are out in the freezing weather with the tractor moving the front axle is nowhere close to ambient.
A lot longer than 10 feet. FWIW Kubota STRONGLY recommends an 8 centistoke fluid in the rear differentials of all their tractors up through 100+ HP M series machines. I dont think the front differential is any more demanding.

Dan
 

kubotafreak

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A lot longer than 10 feet. FWIW Kubota STRONGLY recommends an 8 centistoke fluid in the rear differentials of all their tractors up through 100+ HP M series machines. I dont think the front differential is any more demanding.

Dan
That fluid my friend goes through a tiny little set of gears in a positive displacement pump. Unlike a front differential of a tractor which has no formal pump. Not the same scenario.
Look from a can it survive with thin fluid absolutely. Does it protect as well no it does not. The only reason it does well in the trans/rear diff, is because it is filtered. Sudt2 is a wonder fluid I will give you that. In the front axle scenario it is not as much protection. Kubota knows that as well or they wouldn't offer any alternative. Lighter fluids help bed in better, which is probably the main reason the thing is factory filled with it.
 
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TheOldHokie

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That fluid my friend goes through a tiny little set of gears in a positive displacement pump. Unlike a front differential of a tractor which has no formal pump. Not the same scenario.
Look from a can it survive with thin fluid absolutely. Does it protect as well no it does not. The only reason it does well in the trans/rear diff, is because it is filtered. Sudt2 is a wonder fluid I will give you that. In the front axle scenario it is not as much protection. Kubota knows that as well or they wouldn't offer any alternative. Lighter fluids help bed in better, which is probably the main reason the thing is factory filled with it.
I beg to differ. UTTO is used world wide in the differrentials of hundreds of thousands of common sump tractors made by dozens of OEMs including Kubota, JD, Case, CNH, AGCO, Mahindra, etc. It is a grade 80 GL4 gear oil specifically formulated and tested for use in front and rear final drives of off road equipment. It has a field proven track record over decades of use.

Kubota allows conventional gear oil in the front becsuse it is not circulated like the rear. Since those conventional gear oils are all grade 90 GL5 hypoid formulations desugned for automotive use you are getting a 50% boost in EP treat level and a very minor increase in KV100. "Better protection" yes but in a tractor with low speed spiral bevel front and rear axle differentials thats about like your girl friend taking birth control pills after you had a vasectomy.

Ì am not advocating for either - just pointing out there is no real life performance gain or loss in the front or rear differential of an agricultural tractor. This argument has been beaten to death by the heàvier oils are better curmudgeons on the antique tractor forums.

Dan
 
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hagrid

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I beg to differ. UTTO is used world wide in the differrentials of hundreds of thousands of common sump tractors made by dozens of OEMs including Kubota, JD, Case, CNH, AGCO, Mahindra, etc. It is a grade 80 GL4 gear oil specifically formulated and tested for use in front and rear final drives of off road equipment. It has a field proven track record over decades of use.

Kubota allows conventional gear oil in the front becsuse it is not circulated like the rear. Since those conventional gear oils are all grade 90 GL5 hypoid formulations desugned for automotive use you are getting a 50% boost in EP treat level and a very minor increase in KV100. "Better protection" yes but in a low speed spiral bevel tractor front axle differential applications thats about like your girl friend taking birth control pills after you had a vasectomy.

Ì am not advocating for either - just pointing out there really is no real life performance gain or loss in the front or rear differential of an agricultural tractor. This argument has been beaten to death by the heàvier oils are better curmudgeons on the antique tractor forums.

Dan
CÁT?
 

hagrid

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Hagrid that's a little too opaque for me to decipher this morning.

Dan
I will assistify...

In your post listing various manufacturers that used an 80 grade oil in their finals you didn't list Caterpillar. You also got fancy towards the end with accents over vowels.

Attend your eyes and behold:
Screenshot_20230328_090325_Dolphin.jpg

Screenshot_20230328_090353_Dolphin.jpg

I saw an opportunity to combine two areas of interest with one finely hewn response, also incorporating the additional attribute of brevity.
 
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