Front Axle Oil

[06B3030]

I have a B3030 and planning on changing the front axle oil. The WSM says to use Super UDT, which I have some from when I changed the HST oil, or 80-90 gear oil.

Any suggestions as to which would be better??? I leaning towards using the Super UDT, but figured I'd ask what others have used.

Thanks,
Glenn

 

[Runs With Scissors]

When it's time to do mine, the plan is to use The Super UDT.

And my stupid reasoning is that, they listed it "First".....hahahahah

 

[GrizBota]

Super UDT-2 in both of mine. That’s what they shipped with, so it ought to be fine.

 

[06B3030]

THANKS guys!!!

That's what I was planning on using...but figured I'd check first!

 

[85Hokie]

THANKS guys!!!

That's what I was planning on using...but figured I'd check first!

In your neck of the woods - it will be the better choice. Cold weather has more viscous effect on 80w-90 gear oil.

 

[GeoHorn]

Replaced the SUDT with 80W90 gear oil in mine.

 

[TheOldHokie]

I have a B3030 and planning on changing the front axle oil. The WSM says to use Super UDT, which I have some from when I changed the HST oil, or 80-90 gear oil.

Any suggestions as to which would be better??? I leaning towards using the Super UDT, but figured I'd ask what others have used.

Thanks,
Glenn

Simple question - what's used in the rear differential and reduction gears of every Kubota?

Dan

 

[GeoHorn]

Simple question - what’s been almost universally used in most bevel geared axles for the better part of the century?

(I’m amused that since the last two decades auto/truck makers have switched to sophisticated multi-grade synthetic gear oils…..and then demand that oil be changed every 30K miles since. )

We never had that problem when we used 80W90 gear oil.

 

[TheOldHokie]

Simple question - what’s been almost universally used in most bevel geared axles for the better part of the century?

Since you asked.

In the case of common sump agricultural tractors UTTO has been the standard for the better part of 70 years. I think Ford first introduced theirs (M2C134A) around 1955. Prior to that it was a mild EP (GL3/GL4) gear oil. Kubota was a bit later getting into the game. JD had several variants starting around 1978 with J20A and the current J20C version was introduced in 1989. From a gear lubricant standpoint UTTO is nothing more or less than an SAE 80 GL4 gear oil. As an automotive differential lubricant GL3 and GL4 have been extinct for many decades.

Modern xxW90 GL5 gear oil is primarily designed for use in high speed OTR hypoid gear differentials and is overkill in low speed spiral bevel gear differentials.

Dan

 

[The Evil Twin]

Spiral bevel and hypoid are essentially the same gear set. The difference is where the axis of the pinion intersects the ring.
Straight bevel gears (Kubota front axle knuckles) produce more thrust.
Spiral/ bevel gears slide along the teeth and produce lest thrust, but the thrust force transferred more so to the bearing race.
In any event, my opinion is gear oil for the task. No one is using SUDT2 in their truck differentials. Gear oil does a better job protecting the spiral/ hypoid as it slides. Sure, its not high speed. But that means there is probably less fluid film on the teeth.

 

[TheOldHokie]

Spiral bevel and hypoid are essentially the same gear set. The difference is where the axis of the pinion intersects the ring.
Straight bevel gears (Kubota front axle knuckles) produce more thrust.
Spiral/ bevel gears slide along the teeth and produce lest thrust, but the thrust force transferred more so to the bearing race.
In any event, my opinion is gear oil for the task. No one is using SUDT2 in their truck differentials. Gear oil does a better job protecting the spiral/ hypoid as it slides. Sure, its not high speed. But that means there is probably less fluid film on the teeth.

The tooth geometry of hypoid is vastly different than spiral bevel. For example tooth contact ratio in hypoid can get up around 2.5+. Spiral bevel is right at 1. As a result hypoid can transmit much more torque.

The reason GL5 is needed for hypoid is the loading is much higher requiring a higher EP treat rate. For that reason trucks which commonly have hypoid gears REQUIRE a GL5 gear oil.

Tractors do not have hypoid gears and GL5 is overkill. Use it in the front if you want but the rear which is seeing higher loads and more hours is still running in what amounts to an SAE 80 GL4 gear oil (UTTO).

Dan

 

[The Evil Twin]

The tooth geometry of hypoid is vastly different than spiral bevel. For example tooth contact ratio in hypoid can get up around 2.5+. Spiral bevel is right at 1. Hypoid can rransmit much more torque.

The reason GL5 is needed for hypoid is the loading is much higher requiring a higher EP treat rate. For that reason trucks which commonly have hypoid gears REQUIRE a GL5 gear oil.

Tractors do not have hypoid gears and GL5 is overkill. Use it in the front if you want but the rear which is seeing higher loads and more hours is still running what amounts to SAE 80 GL4 (UTTO).

Dan

Sorta correct. That would depend on the angle of the pinion. That will change the contact ratio as well.
So if we wanna get really technical. All three are "bevel" gears. There are actually four, but Zerol and Spiral are so similar that they often get grouped into one. The front axle gears are essentially straight bevel.
Sure, GL-5 gear oils are typically recommended for hypoid gears in automotive axles operating under high-speed/ high-load conditions.
Your unit may not see much 4wd time, but I don't even know if mine will go back to 2wd. It's never been there since it rolled off the flatbed. Why wouldn't you want to use a cost effective oil that protects better and has a stronger fluid film, more anti scuff additives and withstands temperature extremes better? I mean, if I had SUDT2 left over, sure. Maybe. But I'll use the better, less expensive option.

 

[TheOldHokie]

Sorta correct. That would depend on the angle of the pinion. That will change the contact ratio as well.
So if we wanna get really technical. All three are "bevel" gears. There are actually four, but Zerol and Spiral are so similar that they often get grouped into one. The front axle gears are essentially straight bevel.
Sure, GL-5 gear oils are typically recommended for hypoid gears in automotive axles operating under high-speed/ high-load conditions.
Your unit may not see much 4wd time, but I don't even know if mine will go back to 2wd. It's never been there since it rolled off the flatbed. Why wouldn't you want to use a cost effective oil that protects better and has a stronger fluid film, more anti scuff additives and withstands temperature extremes better? I mean, if I had SUDT2 left over, sure. Maybe. But I'll use the better, less expensive option.

Look we can argue definitions all day long. My point is the rear differential in all of these tractors, many different makes and models from over 70 years is running in UTTO and they do not exhibit wear problems. There is no reason to think the front differential on a Kubota is any different.

Use whatever is convenient for you - I don't think it matters a whit. I own 6 tractors spanning 1941 to 2021 and have many gallons of UTTO sitting around. I don't think I have any GL5 gear oil.

Dan

 

[BAP]

You can use either the UDT2 or the 80-90w. Many dealers recommend using the 80-90w because it is less likely to leak out of the seals in the drop axles where they pivot when turning the wheels, as the seals get worn.

 

[edritchey]

As far as lubrication properties the SUDT2 or the Kubota 80/90 gear oil both would do fine in the front but we always change out the SUDT2 for the 80/90 gear oil at 50hrs the little thicker consistency of the gear oil seems like a better choice IMO and has been used in gearboxes for a long time.

Here's a good video

 

[jyoutz]

Kubota delivers tractors with SUDT in the front axle. I don’t claim to know more than their engineers, so I’m going to continue with the SUDT.

 

[GeoHorn]

….

Modern xxW90 GL5 gear oil is primarily designed for use in high speed OTR hypoid gear differentials and is overkill in low speed spiral bevel gear differentials.

Dan

That’s what I like.… Overkill. Cheaper, more available, overkill.

 

[BAP]

Read your owners manual for

I have a B3030 and planning on changing the front axle oil. The WSM says to use Super UDT, which I have some from when I changed the HST oil, or 80-90 gear oil.

Any suggestions as to which would be better??? I leaning towards using the Super UDT, but figured I'd ask what others have used.

Thanks,
Glenn

If you don’t have a copy of your owners manual, then go onto Kubotabooks and download one for free. The owners manual specifies using Either Super UDT or 80-90w gear oil.

https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=B2630-B3030-B3000%20Operator%20manual..pdf

 

[06B3030]

Read your owners manual for

If you don’t have a copy of your owners manual, then go onto Kubotabooks and download one for free. The owners manual specifies using Either Super UDT or 80-90w gear oil.

https://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor%20Owners%20Manuals/&file=B2630-B3030-B3000%20Operator%20manual..pdf

I have the Owners manual and the WSM for the tractor. I saw both listed and just asked to see what was the preferred oil to use.

 

[GeoHorn]

I have the Owners manual and the WSM for the tractor. I saw both listed and just asked to see what was the preferred oil to use.

80W90 gear oil…. is the “Cheaper, …more available…. Overkill.”

(But since you stated you have some “Super UDT”…. as long as you have sufficient quantity…. you are permitted by Kubota to use that. I personally preferred 80W90 gear oil.