My dealer advised against SUDT

[SkyPup]

Kubota specifically developed SUDT to be utilized in their new GST and HST transmissions, primarily to avoid excessive backpressure @ the hydraulic filters with resulting empty void volume and destruction of the hydraulic pumps and transmissions, which is a real definite problem with the new hydraulics and trannys (not on 30 years old equipment.....).

The SUDT insures longer life and reliabilty of the transmissions and hydraulic pumps than with UDT.

The SAE Technical Paper Series from the International Trends and Developments in Power Fluid for Off-Highway Operation Applications, entitled "Development of High Performance Transmission/Hydraulic Fluid (KUBOTA SUPER-UDT) Establishing the Specification and New Test Method by Nobushige Ichikawa and Tsunejiryo Seno, Senior Lubrication Engineers, Kubota Tractor Corporation, contains the complete specs on the develoment of the Super-UDT hydraulic fluid for Kubota's new GST trannys, HST trannys, and their hydraulic equipment.

 

[bugstruck]

I hear you SkyPup. I have absolutely no reason to doubt your veracity or accuracy on the fluids scene. But answer me this please. Why would Kubota list UDT in my manual as an approved fluid?

The conditions you describe, that would lead to the failure modes your asserting, are probably more likely to occur on equipment that is not well broken in. If that's a fair assumption (even if it's not), why would Kubota put that risk on themselves from the 50 hr. mark on, while still covering a warranty for probably 200 or 300 more hours on the average drivetrain? That 50 hour mark I cite is assuming the machines are factory pre-loaded with SUDT (I've heard that but don't know that) and that Owners like me may make the switch. I know many do. So Kubota is putting themselves at some considerable risk of escalating warranty claims on major components and disgruntled owners, over some black type in a manual? I don't disagree that SUDT is superior in many ways, I'm just not buying that I'm walking in the face of trouble by using their recommended fluid.

Obviously, I'm going to be a tough sell on this. I do admit, I find your attempts most entertaining, in the best sense. You may ultimately convince me to switch back, but not until you've answered some pondering questions in my mind as to why Kubota would do this. Have at it if you like. /forums/images/graemlins/smile.gif

Regards,

 

[5030]

Mike:

Interestingly enough, my newly purchased M9000 that I had to have built and waited almost 2 months for came delivered to the dealer with SUDT. The manual specifically states SUDT for the transmission and/or UDT for the FWA. I personally use (as you know) 85-140 in my FWA in the summer and UDT in the winter. I asked my new and quite knowledgable dealer about the SUDT and he told me the SUDT has better cold climate flow characteristics. It's also more expensive (appreciably) than UDT.

I think this time around, I'll just purchase a 55 gallon drum....less plastic 2.5 gallon jugs to dispose of.

 

[jeffmazz]

"The conditions you describe, that would lead to the failure modes your asserting, are probably more likely to occur on equipment that is not well broken in."



Chris I think it pertains more to cold weather issues....insufficient warm up in cold weather and cold start up in real cold weather where the fluid does not flow quickly enough through the pumps.

The question is: how cold must it be for either fluid to cause damage upon start up? I certainly don't have an answer to that question. I do know that UDT hasn't hurt my BX22 in the 300+ hrs. I have on it. My climate is probably a little cooler than your locale and I use my BX in the winter to plow snow. It was cold last winter(several days machine started on 15-20 degree mornings) and I store the machine in an un heated shed.....Start her up, let her warm up for 10-15 mins. and go to town---no problems as of yet. I agree that SUDT is a better fluid but I think it is more advantageous for those who experience much colder weather than we would normally see and for those who resist proper warm up procedures. Just my opinion.

Best Regards,
Jeff

 

[SkyPup]

It also pertains to water contamination from condesation buildup, which happens in all climates all throughout the year. SUDT is more resistant to having water block the hydraulic filter due to its better emulsion characteristics.

Specifically, SUDT is for GST and HST trannies in all climates all the time, not just during the winter. Kubota spec'd it specifcally for their new trannies.

BTW, the SUDT in Europe and Japan is biodegradable and of a different formualtion that what is available in the USA, so internationally, there are two forms of SUDT, the USA version and everywhere else.

 

[SkyPup]

BTW, Kubota does not spec any engine oil for their engines and never has.

However they DO specify specific oil for their transmissions and hydraulic components. /forums/images/graemlins/wink.gif

 

[jeffmazz]

Skypup,

Good point concerning the condensation buildup. I'm not sure how much of a concern that should be but it is certainly something to consider. If SUDT deals with condensation much better than UDT than it might pay for any of us who store our machines in un heated buildings (colder climates) or store the machines outside to use SUDT. I know that engines burn off condensation in the oil when they run at operating temp for a few minutes. Wouldn't the HST do the same?

Does Kubota publish pour points for both fluids like engine oil manufacturers? I'm curious what the difference might be.

Best Regards,
Jeff

 

[bugstruck]

Jeff, I understand it's primarily the cold weather UDT/SUDT issue that's driving this thread. My point on warranty, etc. and Kubota's recommended fluids is that they have a 3 year drivetrain warranty as I recall. If they are recommending UDT through at least 3 winter cycles on newer equipment, with less operational clearances and more break-in hot spots, you'd have to assume they are beyond reasonably comfortable approving that fluid. Simply put, mechanical assemblies that revolve (generate friction) are more prone to failure in the early hours of life, not less. Add the described cavitation or blocking of fluids.... i.e. failure of fluids to be in all intended locations at intended pressures, to a new machine's operation, and your just asking for problems. That's why I'm puzzled as to Skypup's stance on this. If he's correct, and Kubota engineers share his understanding on this issue, then I would come to the conclusion that Kubota is a glutant for punishment.

Now on the newer M series that was cited as SUDT only, I would think something in the very latest hydro/pump designs has been ground-up engineered around the newer SUDT lubrication. Or perhaps they are moving their specified fluid requirements along in time. It's the newer fluid, and it's the latest tractors, so marry them up. That or they read one of these old SUDT/ UDT threads and got scared. /forums/images/graemlins/wink.gif I just know my late 2004 model still calls out either fluid.

That said, SkyPup makes a good point on condensation and emulsifying capabilities of SUDT. Having been a boat owner I can attest to that being a good thing at any temp. No disagreement there.

 

[SkyPup]

If your hydraulic fluid is hot enough to boil water (212*F), then you are in major trouble as it shouldn't ever get much above 160*F or so. It does NOT operate like crankcase oil.

Our Kubota L-39 GST TLB does have a hydraulic oil cooler due to the severe service it sees, as I would imagine the Kubota HST tranny tractors would too, I don't know for certain, but I would think it mandatory for an HST to have a hydraulic cooler.

The main differences between the two specs are in the kinematic viscosities across a range of temperatures.

The 55 gallons of Amsoil's Full Synthetic 5W-30 Hydraulic fluid that I am using in our L-39 GST TLB, L-3130 GST, and ZD-21 HST match Kubota's SUDT specs!

 

[SkyPup]

BTW, I did run the L-3130 GST on UDT for the first 400 hrs before changing over to SUDT for the second 400 hours.

The difference in fluids was immediately noticeable in both the FEL and the 3pt operation, as was the clutch engagement with the GST electronic solenoids - much smoother, faster, and more fluid. My hydraulic pressure gauge's readings also increased by 75 psi too for some reason?

I would have stayed with the Kubota SUDT @ the 800 hour changeouts had the shipping and transporation of it become recently outrageous.

BTW, does anyone offhand know the cold intake and exhaust valve specifications for the Kubota L-3130?