L4760: What seems to be transmission oil leak

dimka1980

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Kubota L4760
May 14, 2022
14
1
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Eastern Europe
Hi everyone, I have a problem and need some advise. I have what seems to be an oil leak from transmission section, from the place marked on the pictures attached. Can you please let me know what is this "knob" and can it be that oil leaking from there?
 

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Roadworthy

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L2501 HST
Aug 17, 2019
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How much oil is leaking? Does it pool under the tractor or just disappear? If you see no obvious leaks check the level of oil in your crankcase. Sometimes hydraulic oil ends up in the engine when a seal on the hydraulic pump shaft fails.
 
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CGMKCM

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RVT-1100C, ZD323, L4760
Jan 26, 2021
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Randolph county N.C.
I would guess Transmission seal is leaking. That is a housing vent for condensation and no oil should come out of it. I could not find any information about it in owners or service manual. I did find a previous discussion about the Vent .
I also found a exploded parts view that shows the vent and housing see attachment.
 

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chim

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L4240HSTC with FEL, Ford 1210
Jan 19, 2013
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Could it be that the source of the oil is somewhere higher up? The whole bottom looks wet, and it's difficult to believe that he the drip at the opposite end of the casting was blown back for that vent/drain.
 
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dimka1980

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Kubota L4760
May 14, 2022
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Eastern Europe
Hello folks, I will examine higher up to see if leak might be there. But if this air valve leaking oil, I will need to split the tractor to get to that gasket to replace?
 

dimka1980

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Kubota L4760
May 14, 2022
14
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Eastern Europe
Hi guys, seems that the leak is from that vent. And from what I looked at, it seems that I would need to split the tractor to get to the internal seal(s) that are failed. Does anyone have any illustrations or maybe description of what needs to be done and in what order? Thanks
 

woodman55

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L6060HSTC, RTV 1100
May 15, 2022
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Google " kubota on line parts" Kubota has a on line parts break down site, has pt #'s and all. Another good source of info is a work shop manual. Again, google "Kubota WSM" for your model, it's a downloadable pdf file.

Is this a cab tractor ? If so, you will need to remove the cab to access the upper bolts in the bell housing.
 

chim

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Before proceeding with any work, I would get a can or two of brake cleaner and hose that whole area down to get it good and clean. Then I'd run the tractor for a bit and check to be sure that drain is the origin.
 
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dimka1980

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Kubota L4760
May 14, 2022
14
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Eastern Europe
Thanks guys. I downloaded the manual. What happens today though, while examining the issue, I unscrew the bolt of the front wheels drive(not shire how it is called properly, in Russian it is called “front bridge”) I think that bolt is used to check level of fluid, and it just spit oil under pressure, small amount but pressure did build up there…. and it got me thinking, can the oil leak from vent and that pressure somehow connected, can the oil be pushed somehow backwards along the shaft to cause the leak?
 

Mark_BX25D

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Bx25D
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Hi guys, seems that the leak is from that vent.
If it's a vent, it might be that that transmission is overfilled, so some excess is spitting out the vent. In other words, not a seal problem.

I'd double check your level very carefully. Hey, it's free, and it can't hurt!
 

CGMKCM

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RVT-1100C, ZD323, L4760
Jan 26, 2021
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Randolph county N.C.
I have the same model of tractor and I have noticed that the front axel is not vented. Could pressure build up in the axel case and cause a seal to leak? I believe that is possible. I have seen where someone is making a kit to install a vent on the front axle but I think it was for the BX tractors. FYI- My old Kioti tractor had a plastic vent plug on top of the front axle that was a check valve. Pressure could leave the casing but water could not go into the casing.

The front axle is gear oil that has a distinct Oder. Pull the vent out use a pipe cleaner to swab around inside the hole and give it a sniff.
 
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dimka1980

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Equipment
Kubota L4760
May 14, 2022
14
1
3
Eastern Europe
I have the same model of tractor and I have noticed that the front axel is not vented. Could pressure build up in the axel case and cause a seal to leak? I believe that is possible. I have seen where someone is making a kit to install a vent on the front axle but I think it was for the BX tractors. FYI- My old Kioti tractor had a plastic vent plug on top of the front axle that was a check valve. Pressure could leave the casing but water could not go into the casing.

The front axle is gear oil that has a distinct Oder. Pull the vent out use a pipe cleaner to swab around inside the hole and give it a sniff.
I think that the UTTO or UDT was used in the axle so it is the same as the trans oil
 

CGMKCM

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Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
411
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Randolph county N.C.
I think that the UTTO or UDT was used in the axle so it is the same as the trans oil
My factory fill was gear oil and the level was low when I checked everything over when I got the tractor home. Called Dealer and they said top off with Gear oil. Service manual may show both because on the smaller models listed < L4760 use a lighter rated axle and loader. My guess is UDT 2 is fine for that level of load. Pull the front axle fill plug and give it a sniff.
 

dimka1980

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Kubota L4760
May 14, 2022
14
1
3
Eastern Europe
Hello everyone, I wanted to update on this thread and ask for some advise. Ok, I parked the tractor and place a new bucket under that plug, and sure thing over 2-3 weeks entire supply of transmission oil was in that bucket, so I know for a fact that the leak is from that went. However, as you mentioned here, oil should be there and it seems that we have the following. When the water gathered there it wasn't drain and then there was a really cold weather where the water froze. and this gasket (3) I think got ripped. Thoughts?
 

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dimka1980

New member

Equipment
Kubota L4760
May 14, 2022
14
1
3
Eastern Europe
Hello everyone, I wanted to update on this thread and ask for some advise. Ok, I parked the tractor and place a new bucket under that plug, and sure thing over 2-3 weeks entire supply of transmission oil was in that bucket, so I know for a fact that the leak is from that went. However, as you mentioned here, oil should be there and it seems that we have the following. When the water gathered there it wasn't drain and then there was a really cold weather where the water froze. and this gasket (3) I think got ripped. Thoughts?
and if this is the problem, splitting the tractor is the only way to get there, and maybe some of you know what is the part number for this gasket? Thanks
 
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North Idaho Wolfman

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Being that you are in Europe parts for your particular tractor might be different (some EU tractor parts are different than US tractors), Rather a shock to see you are pinging in the center of Russia, I didn't think that was even possible.
Is there a local Kubota parts dealer?
Part numbers for what you want to do are based on serial number, so would need to know that to get you the right part numbers.

Your leak is very likely the seal for the propeller shaft for the 4wd.
it runs through the case just above the spit pin (Clutch housing vent).
You need to talk to a local dealer about the parts (have the serial number off the tractor) because I do believe there was an upgrade kit for that seal.

It's very very unlikely that it's the gasket leaking, could be the seal on the input shaft but that seal normally doesn't leak.

As far as repair goes I think ( but don't know for sure) that that seal on the propeller shaft will come out the front to be replaced. You DO NOT remove the shaft section that is in the transmission, if you do you will be tearing the whole thing apart to reassemble it.

Propeller shaft seal

L4760 Propeller shaft seal.JPG
L4760 HST shaft seal.JPG
 
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dimka1980

New member

Equipment
Kubota L4760
May 14, 2022
14
1
3
Eastern Europe
Being that you are in Europe parts for your particular tractor might be different (some EU tractor parts are different than US tractors), Rather a shock to see you are pinging in the center of Russia, I didn't think that was even possible.
Is there a local Kubota parts dealer?
Part numbers for what you want to do are based on serial number, so would need to know that to get you the right part numbers.

Your leak is very likely the seal for the propeller shaft for the 4wd.
it runs through the case just above the spit pin (Clutch housing vent).
You need to talk to a local dealer about the parts (have the serial number off the tractor) because I do believe there was an upgrade kit for that seal.

It's very very unlikely that it's the gasket leaking, could be the seal on the input shaft but that seal normally doesn't leak.

As far as repair goes I think ( but don't know for sure) that that seal on the propeller shaft will come out the front to be replaced. You DO NOT remove the shaft section that is in the transmission, if you do you will be tearing the whole thing apart to reassemble it.

Propeller shaft seal

View attachment 93945 View attachment 93946
Hi Wolfman,

Thanks for the explanation, I will try and see what I can do without tearing it apart. Can you please let me know the screenshots you have here, where are they from? Is it a online manual or something? I think it will help me review some things there. Thanks
 

North Idaho Wolfman

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Hi Wolfman,

Thanks for the explanation, I will try and see what I can do without tearing it apart. Can you please let me know the screenshots you have here, where are they from? Is it a online manual or something? I think it will help me review some things there. Thanks
Do you have the WSM (aka Service manual)?
The screen shots are from Kubota's parts site online.
 
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