Gear oil vs UDT in front axle

Tractor Gal

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I just watched a video for front axle of BX series. Instead of using the UDT, gear oil 80-90 was going to be used. The rationale was that the gear oil had a little greater viscosity and for the axle, the greater viscosity may actually serve as a better lubricant. Are there any thoughts on this? I am preparing to change the front axle oil. Thanks for the knowledge that I know will come.

TG
 

Roadworthy

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What does your owners' manual say to use? I'd have to check for suue but I think for the 4WD front end my L2501 recommends gear oil. Follow the manual.
 

Tractor Gal

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What does your owners' manual say to use? I'd have to check for suue but I think for the 4WD front end my L2501 recommends gear oil. Follow the manual.
Manual gives both as a choice. I was interested in knowing the experiences of those who have used the gear oil particularly. It would be a lot cheaper, for sure, and the extra viscosity may reduce some leaking.

TG
 

Captain13

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From Kubota Lubricant and Maintenance tables, UDT or 80-90 gear oil is acceptable. I just completed my 600 hour maintenance on the M7040 and went with the gear oil. Why??? Because i drained gear oil out. That’s what was in my tractor. I live in Georgia and feel more comfortable running gear oil because of the heat. Plus, plowing and using a box blade are almost always done in 4WD. Supposedly, there is no difference in lube capability between the two. Mine is a personal preference. The gear lube is slower to drain, and to put back in. 80-90 synthetic is definitely more expensive than UDT. Decisions, decisions.
 

Tractor Gal

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From Kubota Lubricant and Maintenance tables, UDT or 80-90 gear oil is acceptable. I just completed my 600 hour maintenance on the M7040 and went with the gear oil. Why??? Because i drained gear oil out. That’s what was in my tractor. I live in Georgia and feel more comfortable running gear oil because of the heat. Plus, plowing and using a box blade are almost always done in 4WD. Supposedly, there is no difference in lube capability between the two. Mine is a personal preference. The gear lube is slower to drain, and to put back in. 80-90 synthetic is definitely more expensive than UDT. Decisions, decisions.
Good insight. And, yes, I was thinking about the cost after I said gear oil would be cheaper...not necessarily, as you mention. My goal is to reduce the little bit of seepage that I see. I don't want to deal with replacing seals right now. Thanks for taking time to share. Yes...decisions, decisions, decisions. :)

TG
 

armylifer

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I have not changed mine yet but I plan on using gear oil when I do. I originally planned to do it today but our govenor closed everything up because of covid. Now I guess I have to order from amazon.
 

Tractor Gal

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I have not changed mine yet but I plan on using gear oil when I do. I originally planned to do it today but our govenor closed everything up because of covid. Now I guess I have to order from amazon.
If I may press the issue a bit...are you planning on synthetic gear oil or regular? I'm leaning toward regular but that could be from my ignorance of what actually goes on in that axle. It doesn't seem that there would be that much stress/strain. The object is to keep the parts lubricated. Does synthetic do that better? I don't know. Maybe that's why it was created. On the other had, if it is thinner, it may defeat the purpose that I have to reduce seal seep.

TG
 

armylifer

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I do not use any synthetic lubricants of any sort. It is my opinion that they are a waste of money. This reply is sure to get a lot of people to chime in and "correct" my thought process. I have been using the same old petroleum products for more than 50 years and never had a problem.
 
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Tractor Gal

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I do not use any synthetic lubricants of any sort. It is my opinion that they are a waste of money. This reply is sure to get a lot of people to chime in and "correct" my thought process. I have been using the same old petroleum products for more than 50 years and never had a problem.
Makes sense...if it ain't broke, don't fix it! :) Thanks.
 

Luckystars

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It's been my experience that full synthetic changeovers always result in leaks or oil consumption. We have a Toyota that was started on synthetic and no issues.
I 'think' it has smaller molecules and not only flows better but flows where the conventional oil can't.
If the book calls for either you can't go wrong.
 
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85Hokie

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I do not use any synthetic lubricants of any sort. It is my opinion that they are a waste of money. This reply is sure to get a lot of people to chime in and "correct" my thought process. I have been using the same old petroleum products for more than 50 years and never had a problem.
I'll chime in and disagree with you 100% :)

I use Amsoil 80w90 in my BX front end and Rotella T6 5w-40 in my BX engine - S-UDT2 in my HST
Amsoil 0w20 in my Subaru.....and if I am really cheap, Mobil 1 5w30 in my GMC:p

AS for the money aspect - the Mobil 1 is the same price as dyno oil and the Amsoil cost me about 10% across the board.

Army, I aint trying to bust your chops .....but would you really use 30w straight on a 8n if you had one - toady? I know it said to use it in 1948-1952 but like SOME things, new stuff really can be better than "old" stuff. (Not true with all things!:love:)

I am one of these people that can read and understand how and what oil is made of - and yes I do believe in scientific data when it is backed up with a sht load of years of testing and data - but we'll save that for anther day!;)
 
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Tractor Gal

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It's been my experience that full synthetic changeovers always result in leaks or oil consumption. We have a Toyota that was started on synthetic and no issues.
I 'think' it has smaller molecules and not only flows better but flows where the conventional oil can't.
If the book calls for either you can't go wrong.
Now that you mention it, I think I have heard that said about synthetic in older engines. I wouldn't know about in an axle case. But...something to think about. Thanks.
 

armylifer

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I'll chime in and disagree with you 100% :)

I use Amsoil 85w90 in my BX front end and Rotella T6 5w-40 in my BX engine - S-UDT2 in my HST
Amsoil 0w20 in my Subaru.....and if I am really cheap, Mobil 1 5w30 in my GMC:p

AS for the money aspect - the Mobil 1 is the same price as dyno oil and the Amsoil cost me about 10% across the board.

Army, I aint trying to bust your chops .....but would you really use 30w straight on a 8n if you had one - toady? I know it said to use it in 1948-1952 but like SOME things, new stuff really can be better than "old" stuff. (Not true with all things!:love:)

I am one of these people that can read and understand how and what oil is made of - and yes I do believe in scientific data when it is backed up with a sht load of years of testing and data - but we'll save that for anther day!;)
No offense taken at all. I just knew that someone would disagree with me, I just did not know who. Anyway, if I owned an 8N I would use 10W30 or 10W40 dino motor oil. The older engines especially need to use non-synthetic because those engines have looser tolerances and need the higher viscosity oils.

The point about Mobile 1 is no longer valid since they started using dino stock as their base instead of the old fully synthetic stock.

I once used Mobile 1 in my 1982 Toyota Tercel The car ran great but started leaking oil from the pan. The car was originally run on dino for the first 50,000 miles or so when I changed over to Mobile 1. After experiencing the leaky oil change, I went back to dino and the leaks stopped. Since that time I have never experimented again. I just went back to the old tried and true, and never looked back.
 

Magicman

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A good rule of thumb is to never change from one type of oil/lube to another, especially in an engine and more especially in an older engine.
 
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85Hokie

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A good rule of thumb is to never change from one type of oil/lube to another, especially in an engine and more especially in an older engine.
Again - not to open Pandora's box on oils ............ the secret to old sloppy engines is to use a HIGH viscosity oil that will "fill" those wonderful gaps between those sloppy moving parts! Synthetics can be made to flow freely at 0 weights and they make a nasty 60w straight synthetic that is used in dragsters that is almost like molasses!(ok - that was a stretch!)

The unfortunate truth is that most all oils within a certain range will a viscosity of water when they have been heated to 100c

As for switching back and forth ...... that too have been around a long time, as well as "allow the engine to break in before using synthetics...."

funny how we have gone from flat earth to round earth to some in the flat range again!

The real truth - ANY oil you pick up in the last 10 years will work in almost any circumstance - oil today is lightyears advanced as to what it was 70 years ago. The scientists that make the stuff - are working on the molecular level ...... hell it will not be long before some company produces a nanobots that can go INTO an engine and somehow rebuild those places that need a lot of TLC all the while in the oil !!!
 

armylifer

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Again - not to open Pandora's box on oils ............ the secret to old sloppy engines is to use a HIGH viscosity oil that will "fill" those wonderful gaps between those sloppy moving parts! Synthetics can be made to flow freely at 0 weights and they make a nasty 60w straight synthetic that is used in dragsters that is almost like molasses!(ok - that was a stretch!)

The unfortunate truth is that most all oils within a certain range will a viscosity of water when they have been heated to 100c

As for switching back and forth ...... that too have been around a long time, as well as "allow the engine to break in before using synthetics...."

funny how we have gone from flat earth to round earth to some in the flat range again!

The real truth - ANY oil you pick up in the last 10 years will work in almost any circumstance - oil today is lightyears advanced as to what it was 70 years ago. The scientists that make the stuff - are working on the molecular level ...... hell it will not be long before some company produces a nanobots that can go INTO an engine and somehow rebuild those places that need a lot of TLC all the while in the oil !!!
Your statement that any oil in the last 10 years will work in almost any circumstance is absolutely correct. There is no oil made that does not have synthetic molecules in it. That is how multi-weight oils are made now. So, extrapolating that little tidbit, all oils are actually synthetic nowadays.
 
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Thunder chicken

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I’m running SUDT in the axle on the M7060. But I operate in the winter,(-30’s) sometimes cold starts outside (I’m not gonna put a pan heater on the axle) so the thinner oil is better for that IMO. And it’s what the book says to use so it can’t hurt. If I was in a warmer climate I’d think 80w90 would be fine or better, and I’d also hazard a guess that synthetic vs non in a tractor such as a BX that gets a few hundred hours a year at most of use it would never matter. Placebo effect!!!
 

PoTreeBoy

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T G, I put gear oil in my old L35 for the same reasons you gave. I think that's what drained out. I can't remember for sure, but I think I used conventional. If I lived and used it in extreme cold weather, I would probably use UDT.
 

Nicfin36

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I put 80W90 in my L2501 front axle. The manual says UDT or 80W90 gear oil is fine for mine as well. The most important thing is to have one or the other rather than NONE. Mine had virtually none in it when I checked it. A very common problem it seems as incompetent dealers do not properly fill them when they prep the tractor.

I think you would be fine with either one. Since I'm in the south, I chose to use 80W90 as cold will never be a factor.
 
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