Mixing UDT and Gear Oil

Horst

New member

Equipment
Bx23s
Oct 23, 2021
3
0
1
Canada
Hello,

I tried to search in the forum and online, but haven’t been able to find an answer.

Here is my problem, need to top up the front axle on my bx23s , but I don’t know which fluid to use. I know the manual says UDT or gear oil.

BUT, after grabbing some UDT to top
off my transmission from the dealer, I asked the parts guy to confirm that I can mix the two in the front axle and the guy said not to do that.

So I asked him to confirm if the tractor came from the factory with UDT or gear oil and he said gear oil (he confirmed with one of their techs). Now if I look online all I can find is people saying my that Kubota fills these with UDT from the factory.

Now I don’t know what to do, top up the axle with UDT or gear oil?

Why would Kubota say in the manual to use either fluid but not add a warning not to mix the two.

The tractor has 27h on it, so it definitely has the factory fluid in it.
 

Nicfin36

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Equipment
L2501 HST, BH77 Backhoe, SSQA Loader ZD1011 Mower
Jun 19, 2019
1,016
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83
Decatur, AL
You can just drain and fill with UDT if you really want to make sure. I don't think your tractor even holds 4 qts. The dealer told me they use UDT in everything. However, they never checked mine and it was 4 qts or so low on my L2501.

I doubt that it would hurt to mix. I would gladly have had 50% UDT and 50% gear oil rather than 4 qts low.
 
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MOOTS

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MX6000
Jun 27, 2019
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When I got my MX home, I checked and serviced everything, as it was used. Don't know what was in it, but I topped off with about a quart or so of gear oil.
 
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Henro

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B2910, BX2200, KX41-2V mini Ex., Beer fridge
May 24, 2019
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Hello,

I tried to search in the forum and online, but haven’t been able to find an answer.

Here is my problem, need to top up the front axle on my bx23s , but I don’t know which fluid to use. I know the manual says UDT or gear oil.

BUT, after grabbing some UDT to top
off my transmission from the dealer, I asked the parts guy to confirm that I can mix the two in the front axle and the guy said not to do that.

So I asked him to confirm if the tractor came from the factory with UDT or gear oil and he said gear oil (he confirmed with one of their techs). Now if I look online all I can find is people saying my that Kubota fills these with UDT from the factory.

Now I don’t know what to do, top up the axle with UDT or gear oil?

Edit: By the way, Kubota seems notorious for not completely filling front axles, especially on BX models, with oil...Likely yours is one of many. Did you check it when you got it? 27 hours is not much...

Why would Kubota say in the manual to use either fluid but not add a warning not to mix the two.

The tractor has 27h on it, so it definitely has the factory fluid in it.
I have read MANY times that UDT is the fill on Kubota front axles, or maybe SUDT, not sure. BUT certainly not normal gear oil.

I would just add the UDT and be happy. If you are really concerned, you might take a sample of what is in there and compare it to the thicker gear oil. But likely not necessary.

As mentioned above, if you are really in fear, drain what is in there and add the UDT or SUDT, and remember what to add next time.
 
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Horst

New member

Equipment
Bx23s
Oct 23, 2021
3
0
1
Canada
When I got my MX home, I checked and serviced everything, as it was used. Don't know what was in it, but I topped off with about a quart or so of gear oil.
Yeah I wish I had done that, I checked the fluids a couple of times and there was oil on the dipstick, but I never wiped it off and put it back in to properly check it, as I assumed it came filled to the right level from the dealer. Both, the front axle and transmission appear to be just below the dipstick ... Well, lesson learned, everything worked fine while I was using it so I hope no harm was done.

Thank you for the replies, I might just drain it and put the UDT in so I can sleep at night :rolleyes:
 

MOOTS

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MX6000
Jun 27, 2019
1,928
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Canton, Georgia
Yeah I wish I had done that, I checked the fluids a couple of times and there was oil on the dipstick, but I never wiped it off and put it back in to properly check it, as I assumed it came filled to the right level from the dealer. Both, the front axle and transmission appear to be just below the dipstick ... Well, lesson learned, everything worked fine while I was using it so I hope no harm was done.

Thank you for the replies, I might just drain it and put the UDT in so I can sleep at night :rolleyes:
Just to clarify, I didn't drain the front axle, just topped it off with gear oil I had on the shelf from the Jeep days.

It's just bearings and gears up there, nothing fancy. Something slippery will keep it happy.
 
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xrocketengineer

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Nov 14, 2020
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Just to clarify, I didn't drain the front axle, just topped it off with gear oil I had on the shelf from the Jeep days.

It's just bearings and gears up there, nothing fancy. Something slippery will keep it happy.
That is exactly what I did.
 
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tinkerwitheverything

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bx2370-1
Jun 3, 2015
319
72
28
Manitoba
Gear oil has it's own smell . Just wipe a bit onto a rag take a whiff of it and compare it to gear oil in the new container. Anyone can smell the difference of gear oil.
 
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MOOTS

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MX6000
Jun 27, 2019
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Canton, Georgia
Gear oil has it's own smell . Just wipe a bit onto a rag take a whiff of it and compare it to gear oil in the new container. Anyone can smell the difference of gear oil.
Stank. That is the word your looking for. Of all the fluids in anything, gear oil straight stinks!
 
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Norman

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LX2610HSD;LA535;LP 60" grapple; WC68 chipper; GB60 SW cutter
Sep 30, 2021
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Georgia, USA
I picked up my new LX2610 today and the dealer told me more than once that they use gear oil in the front axle and Udt2 everywhere else.

also, in my experience with Jeeps, gear oil has a distinct smell. Not sure how much it varies from hydraulic fluid though.
 
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xrocketengineer

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BX1880, FEL, Grapple, 36 in. Forks, 48in. MMM, Quick Spade, Ripper
Nov 14, 2020
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Merritt Island, Florida
Yeah I wish I had done that, I checked the fluids a couple of times and there was oil on the dipstick, but I never wiped it off and put it back in to properly check it, as I assumed it came filled to the right level from the dealer. Both, the front axle and transmission appear to be just below the dipstick ... Well, lesson learned, everything worked fine while I was using it so I hope no harm was done.

Thank you for the replies, I might just drain it and put the UDT in so I can sleep at night :rolleyes:
If you are going to drain it completely, your best bet would be the gear oil in the long term because it will cut down on leaks. Additionally, you need to remove the two "vent plugs" (one on the top of each wheel gearbox) and fill each side to that level to ensure no air in the system. Then replace the plugs and recheck the level with the dipstick and add more oil if necessary.
 

Nicfin36

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Equipment
L2501 HST, BH77 Backhoe, SSQA Loader ZD1011 Mower
Jun 19, 2019
1,016
466
83
Decatur, AL
If you are going to drain it completely, your best bet would be the gear oil in the long term because it will cut down on leaks. Additionally, you need to remove the two "vent plugs" (one on the top of each wheel gearbox) and fill each side to that level to ensure no air in the system. Then replace the plugs and recheck the level with the dipstick and add more oil if necessary.

I see the OP is in Canada. He might be better off with UDT or even better yet Super UDT since he might be operating in extreme cold temps.
 

ItBmine

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Equipment
B2620, RTV-X1100C
Jan 21, 2014
1,378
384
83
Canada
I replaced the front axle oil in my B when I did the first 50 hour service and I had bought gear oil for it, but when I drained it was far thinner than gear oil. So I used SUDT since I'm in a colder climate anyway.
I later confirmed with a Kubota rep at a dealer show I got invited too, that UDT is just fine in the front axle.
 

SRRGC1

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Equipment
BX1870-1, BX23S TLB, RTV XG850, MX5100DT
Jan 6, 2021
212
75
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Bloomsburg
Hello,

I tried to search in the forum and online, but haven’t been able to find an answer.

Here is my problem, need to top up the front axle on my bx23s , but I don’t know which fluid to use. I know the manual says UDT or gear oil.

BUT, after grabbing some UDT to top
off my transmission from the dealer, I asked the parts guy to confirm that I can mix the two in the front axle and the guy said not to do that.

So I asked him to confirm if the tractor came from the factory with UDT or gear oil and he said gear oil (he confirmed with one of their techs). Now if I look online all I can find is people saying my that Kubota fills these with UDT from the factory.

Now I don’t know what to do, top up the axle with UDT or gear oil?

Why would Kubota say in the manual to use either fluid but not add a warning not to mix the two.

The tractor has 27h on it, so it definitely has the factory fluid in it.
I used to work for a Kubota dealer for 10 yrs. Our service dept. would always use gear oil in the front axle UNLESS the customer wanted SUDT. I currently own 2 bx's, BX 1870 and BX 23S tlb. I drain both at the 50 hr service and used gear oil. I believe they both had SUDT in the front axle.
 

Fordtech86

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L3200
Aug 7, 2018
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Just a thought since these threads come up often…

What do y’all use in the rear axle?
 
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