Kubota rear axles/differentials

   / Kubota rear axles/differentials #1  

om21braz

Veteran Member
Joined
Jun 1, 2004
Messages
2,171
Location
Lexington, NC
Has anyone here ever had any problems with rear axles/diff. or the seals on the Kubota machines. I'm assuming most of you have not and I'm positive that Kubotas' engineers are far more educated than me - but I'd prefer seeing the diff. case/housing come out much closer to the hub end of the axle for more support. I'm sure it's went through numerous tests, etc. - but it just don't look right to this old dumb country boy.
Just to be clear, I'm not referring to the portion allowing for wheel spacing adjustment.
 
   / Kubota rear axles/differentials #2  
I had to have both rear seals (where the axles exit the transmission) replaced due to leakage. B2410 tractor is 2 years old and had around 85 hours on it. Repair was covered under warranty. Mechanic told me that he wasn't impressed with the design of the seals. He indicated that he would have liked to see a dust cover on top of the seals.

Hope this helps.
 
   / Kubota rear axles/differentials #3  
I think I may know what you are refering to - the fact that at the wheel centerline there isn't a shaft and housing that goes all the way from one side to the other - instead there are separate "gear reducers" for each rear wheel hub. My 1982 L345 DT was built like that - and the reducer housings were formed steel - not cast iron like the newer ones. But they held up just fine. Hope this is relevant to your question. Takle care, Dick B
 
   / Kubota rear axles/differentials
  • Thread Starter
#4  
</font><font color="blue" class="small">( I think I may know what you are refering to - the fact that at the wheel centerline there isn't a shaft and housing that goes all the way from one side to the other - instead there are separate "gear reducers" for each rear wheel hub. )</font>

You're close. The fact they are separate, that is understandable - but that the housing is'nt longer on each side exposing less of the actual axle and placing the bearing out further giving more support to the axle. I expect it is due to cost cutting - think about making the housing on each side a few inches shorter on thousands of tractors - adds up quickly. But as mentioned earlier, I would expect Kubota to have calculated the stress and determined it is enough support to do the job - maybe not overkill as things used to be built. Thanks for the replies !
 
   / Kubota rear axles/differentials #5  
In some cases this may be done because there are narrow and standard width versions of the same tractor.

I don't know, but perhaps when a narrow version is produced, they then only have to install shorter axles rather than produce two different housings...

My B2910 has about six or more inches of axle protruding beyond the axle housing...

There are also rear track assemblies that bold onto the rear axle housing in Japan that are used in place of rear wheels. Maybe this has something to do with the design also?

Attached is a photo of a small tractor with tracts installed (15 hp) but I have seen them on larger tractors as well...
 

Attachments

  • 440970-2.JPG
    440970-2.JPG
    75.4 KB · Views: 824
   / Kubota rear axles/differentials
  • Thread Starter
#6  
</font><font color="blue" class="small">(
There are also rear track assemblies that bold onto the rear axle housing in Japan that are used in place of rear wheels. Maybe this has something to do with the design also?)</font>

Henro, that may very well be why it's designed as it is and one less style of casing to stock - neat pic of the Bota' w/ tracks !
 
   / Kubota rear axles/differentials #7  
I believe you are creating an issue that does not exist. Most tractors I believe have exposed axles beyond the housing and whether they do or not really does not matter. On some Kubotas the wheels can move in and out on the axle shaft for different positions. If the housing went all the way out to the wheel this would not be possible. The axle is sized to carry the weight and loads imposed on it. If you bend one of these axles then in a similar situation you would have cracked a full length housing. J
 
   / Kubota rear axles/differentials #8  
With the idea that bending an axle would fracture an imaginary extension to the casing ... what do you experienced folks say about this situation? My 17hp Kubota managed to (over-)load it's 3 point system to such an extent that it now has a ruined [fractured in two] hydraulic cylinder case and a badly damaged top rear edge on the differential case; the edge damage is a consequence of the hydraulic cylinder case getting ripped off of the tractor.
Looking at the damage causes me to wish the tractor had been designed so that an (over-)load would break the lift arms rather than allowing them to transfer the (over-)load to their shaft which then fractured the hydraulic cylinder case.
 

Attachments

  • Damaged Kubota.jpg
    Damaged Kubota.jpg
    897.1 KB · Views: 1,776
   / Kubota rear axles/differentials #9  
With the idea that bending an axle would fracture an imaginary extension to the casing ... what do you experienced folks say about this situation? My 17hp Kubota managed to (over-)load it's 3 point system to such an extent that it now has a ruined [fractured in two] hydraulic cylinder case and a badly damaged top rear edge on the differential case; the edge damage is a consequence of the hydraulic cylinder case getting ripped off of the tractor.
Looking at the damage causes me to wish the tractor had been designed so that an (over-)load would break the lift arms rather than allowing them to transfer the (over-)load to their shaft which then fractured the hydraulic cylinder case.

The tractor did not overload the 3-point, the operator did.
 
   / Kubota rear axles/differentials #10  
Were you using a logging winch or 3 point backhoe? Common damage from that type of use on compacts.

Re the axle length, my 5030 doesn't stick out far beyond the casting. Take a look at ag tractors with axle mounted duals, they have about 3 feet of axle sticking out beyond the casting face.
 
 
Top