L4760: What seems to be transmission oil leak

dimka1980

New member

Equipment
Kubota L4760
May 14, 2022
9
0
1
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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Lifetime Member

Equipment
L2501 HST
Aug 17, 2019
1,397
348
83
Benton City, WA
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

Active member

Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
156
65
28
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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Equipment
L4240HSTC with FEL, Ford 1210
Jan 19, 2013
1,227
303
83
Near Lancaster, PA, USA
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

New member

Equipment
Kubota L4760
May 14, 2022
9
0
1
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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Equipment
Kubota L4760
May 14, 2022
9
0
1
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

Active member

Equipment
L6060HSTC, RTV 1100
May 15, 2022
250
135
43
canada
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

Well-known member

Equipment
L4240HSTC with FEL, Ford 1210
Jan 19, 2013
1,227
303
83
Near Lancaster, PA, USA
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

New member

Equipment
Kubota L4760
May 14, 2022
9
0
1
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

Well-known member

Equipment
Bx25D
Jul 19, 2020
746
440
63
Virginia
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

Active member

Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
156
65
28
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

New member

Equipment
Kubota L4760
May 14, 2022
9
0
1
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

Active member

Equipment
RVT-1100C, ZD323, L4760
Jan 26, 2021
156
65
28
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.