Kubota fluid quandry?

Welcome to the forum. Congrats on the orange tractor repair and keeping it going.


Here is the deal on the fluid as I have just crossed all those bridges in building my L175 back to life.

First the manual is "1978" which is extremely dated by way of fluid technology! While I am not saying the wheel has been re-invented since then there are some HUGE advancements in chemical and oil capabilities that even Kubota has embraced which requires some changes for now.

Even a Kubota dealer may not know/understand oil properties and steer a person wrong simply because some of them have a salesperson disposition; it's not theirs and they don't understand the technology of the machines that they sell anyway, your just supposed to buy it.

That said, oil is largely misunderstood when it comes to clearances, viscosities and dissipation properties so be very guarded with answers and make sure that your best interest is aligned with the facts and/or their answers.

In an effort to keep this rant short I will give short answers/explanations and we can expound on singular elements in further posts if interested.

The updated manuals which have been written by/or for Kubota products take into consideration the advancement of oil and for most all Kubota products "Kubota UDT" is recommended where open faced gears and hydraulics are running together. Some of these later manuals explain that the "old" heavy weight oil spec, 80WT, is to be disregarded and some don't and just simply say use UDT oil.

Trans fluid is more of a "get by" solution for a field repair but should never be used as the permenant fluid to replace UDT. Some do because it it cheap but repairs due to the inabilities of the fluid are COSTLY!

The enviornment in the trans tunnel is very diverse and harsh to two types of mechanical operations that are not separated and have to use the same lubrication. Both the drive gears and the hydraulic pump have to use the same fluid which is technically not suite for both functions. For this reason Kubota engineers their fluid, not too much different from most other tractor UDT's, with additives that help both uses. For the open faced gear there is pressure/friction modifiers to reduce drag/wear but keep adequate lubrication. For the Hyd pump additives are used to keep particles from "holding" in suspension and causing damage to the pump. Even a very small particle as small at 25 microns, to small to see whith the human eye, can damage hydraulic pumps and components of the hyd system. Of course gears are going to give off wear but with the proper fluid there is control against the wear particles causing damage to other areas.

With heavier fluids in times past all this was assumed to be optimized by the selection of the fluid weight but now all this is accomplished in better and different ways.

Ok so take back that bucket of dope that you bought and get Kubota UDT and you will not have any regrets.
You can even compare the Kubota fluid with the other two fluids and you will see the strange difference in it: thicker than trans fluid and at the same time thinner than the heavy dope but has all the protection for the tractor's systems that have to use it.

There is a "super" UDT and a "heavy" UDT. I doubt that you would need the super in an old "L" tractor. You can select based on your use because that is the only difference in the two.

I just bought six gallons of Super UDT last week. It was about $145 total.

Yep....well said Aquaforce.

I have just changed my L305DT's hydraulic oil and put in a Kubota approved hydraulic fluid...a pail and a half roughly.
My shop manual said to use 80 weight gear oil...not gonna do it!

The local Kubota mechanic said that his father had a Kubota where he used 80 weight gear oil and burned out the hydraulic pump.

Do use a good 80 weight Hypoid oil in the front end diff and drive though.

Hey thar Rrawhide, make sure you pull out your hydraulic filter/strainer and either clean it out or buy a new one before you run the engine after the new UDT gets poured in there.

Later...

Kubotabee.

If I heard correctly, UDT is a 30 weight oil and Super UDT is a 20 weight oil, which explains why they recommend the Super in colder climates. At the dealership I work at, we use Super in every hst transmission and gst transmission. When they give you the choice of gear oil or UDT in front axles we generally use the UDT, and have not seen any problems. Anybody see failures with the UDT in front axles? I always thought a heavier gear oil would do a better job but with all the new tractors, they come standard with the udt. I guess if the hyd oil is good enough to lube a rear differential, it is good enough for a front axle.

This sounds like a situation I got into Friday. We pulled out the 307 Bush Hog that hasn't been used since long before my FIL passed away and I checked the gearbox and it was way low so I dug out the manual and it says SAE140 non-foaming Gear Oil. I'm like wow that some thick oil, went to the nearby Bush Hog dealer and he didn't have any so at the nearby JD dealer they had 85W-140 and they said it was the most compatible oil they had for the gearbox. Napa didn't have the 140 either. It was exactly 1 quart low.

BTW: I downloaded a new manual from Bush Hog yesterday and it now says: EP80-90 gear oil. Is the new manual talking about a different gearbox, who knows.

rrawhide said:

Quandry???????????????

I have a 1978 Kubota L245DT. I have the original operators manual and the specification maintenance sheet too.

I have owned this tractor for 30 years and it has been a good one. HOWEVER, I just broke a rear axle and am in the process of fixing it. All done and ready to go back together.

THEN, I notice the spec sheet and manual shows that the transmission fluid recommendations are 80 WT GEAR OIL. Since this is where all the fluid comes for the tranny and rear end and loader and 3 point it just makes me wonder if this is not way toooooo heavy of oil. I have ALWAYS used transmission fluid. Seems to work just fine and there are a couple of very minor fluid drips occasionally but no big deal on that.

A friend that is a professional mechanic is helping me with this. He suggested that we use only 80 Wt. per specs in manual. Never using this before sure makes me wonder if stuff will still work. I bought a 5 gal pail of 80 wt but have not dumped in yet.

There is not a separate reservoir for the loader so it comes thru the system.

What is the correct answer? please help - quandry??????????

thanx

rrawhide
rrawhide@ocsnet.net

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rrawhide,

Welcome to the board. I have an L175 that is from the 70's; I used universal Hy-trans fluid from the local farm store in mine, (it was full of water when I got the tractor). Check some of the articles that Service Dept Vic has put up on this site, regarding fluid choices. I believe he uses fluid from Walmart, the only reason I didn't was there was a sale on when I bought mine.

I use the same stuff in the transmission of my old Allis Cahalmers WD, it works fine there also.

The only place I use 80 or 90 wt gear oil any more is in differentials or plain gearboxes, such as brush hogs, post hole diggers, and steering boxes.

Robert

Robert

To anyone wondering about oil quality that is not "Kubota" brand. Kubota, (or Dodge, Chevrolet, Ford...) do not make/refine oil! It is manufactured by one of the oil companies then placed in a bucket and branded whoever is buying it. I personally would stick with a more well known brand, but I don't think you'll go wrong buying a lube that is rated for Kubota UDT.

Theekillerbee said:

To anyone wondering about oil quality that is not "Kubota" brand. Kubota, (or Dodge, Chevrolet, Ford...) do not make/refine oil! It is manufactured by one of the oil companies then placed in a bucket and branded whoever is buying it. I personally would stick with a more well known brand, but I don't think you'll go wrong buying a lube that is rated for Kubota UDT.

Click to expand...

For the most part that is the way the market and industry works. One other part that is unique to brands though is that each maker's engineers have an additive specification that is required for their own brand "mix". How much rust inhibitors or how much zinc, phosphorous etc is different based on what each brand values for it's product. For this reason there are differences in enhancements of an oil blend that are targeted for a specific machine due to it's tolerances, use, design and so forth. In times past these differences were much smaller. Now these differences are very noticeable by simply changing the fluid and operating the machine to observe immediate changes in functions.
I wouldn't say any mfgr has reinvented the wheel but with the chemical advancements in techonolgy each mfgr stuff works best as designed and sometimes the design requires that "best" will only be suited by their own recipie.

ok you guys have lost me any chance you could list the oils i need
Kubota L3250
many thanks