Hydraulic System vs VHT transmission

On an X1100, there are two hydraulic filters that the owners manual describes as transmission filters. One is called "suction" in addition to "transmission" filter.
We also have a "hydraulic system with a tank that holds 19 qts of Super UDT whereas the "transmission" capacity is 1.8 gals. I am assuming that the word "transmission" refers to the entire hydrostatic drive system. Is the "hydraulic" system used for the cargo box lift and power steering only? Is there any connection between "transmission" oil and "hydraulic" oil systems? Is the mechanical "gear change" part of the transmission integrated with the VHT system and served by the same oil? Why so much more oil capacity in the "hydraulic" system as compared to the "transmission" system? (9 qts vs 1.8 gals) One would think it would be just the opposite. Also, if the two systems are independent and the two filters serve just the VHT transmission, why is there not a filter on the hydraulic system? The owners manual description of the "systems" leaves something to be desired. Anybody out there that has a better understanding of these "systems"?

doublejack said:

Is the "hydraulic" system used for the cargo box lift and power steering only?

Is there any connection between "transmission" oil and "hydraulic" oil systems?

Is the mechanical "gear change" part of the transmission integrated with the VHT system and served by the same oil?

Why so much more oil capacity in the "hydraulic" system as compared to the "transmission" system? (9 qts vs 1.8 gals)

Also, if the two systems are independent and the two filters serve just the VHT transmission, why is there not a filter on the hydraulic system?

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Yes, hydro system is just the steering and dump box cylinder. And the RTV1100 2008 had two pumps, the smaller for steering and the larger for the dump box, both combined into on unit with the dual output.

No, no connection between the Transmission and Hydraulic systems.

Yes the VHT/Transmission SUDT or UDT fluid does all parts of that system.

Your oil capacity figures are wrong. I go by 12 Liters trany and 17 Liters hydraulic. The quarts listing in this table is wrong. And the trany took less than 11 liters when I changed mine long ago. Hydraulic tank I believe was very close to the 17 liters.

Transmission
12 liters = 12.68 us quarts
17.5 liters = 18.49 us guarts

Work shop manuals are not always accurate. haha

On my RTV1100 2008 it had a filter for the hydraulics mounted on the drivers side inside the frame rail under the dump box.

Hope this helps.

It helps if you add a signature line with the model and year of your rig so others know what you have. Makes it easier to answers questions as the models change over the years.

I believe the x1100 would be the new model if he stated it right. Spudhauler, like you said it is good to have your equipment listed in your signature, it would make it alot easier to identify the correct vehicle.

Too funny, guess I should update my own signature. ha ha ha ME BAD.

Thanks.

And that is why I specified the RTV1100 2008 because even the old, now old, models changed a little each year.

I'm just laughing at myself now. Imagine telling others to do the right thing and I ignore myself. dah!!!

Spudhauler, you do what ever you want, you always have valuable information to share. Receiving a lot of info from your posts that might help me someday.

DoubleJack you are in the same boat as I was for changing the oils in the 1120. Here is what I found the hard way since I burned out the VHT in mine. I did the service at 49 hours draining the oil in the transmission and changing the two filters you talk about. Upon filling the transmission and running my 1120 the transmission did not shift correctly. I changed the oil again and put the old filters back on thinking some how I got a bad filter. The machine ran real bad then. Again I changed the oil in the transmission and put the new filters back on. It now would not move! I took it back to the dealer350 miles away, and they were temporarily puzzled. Upon closer inspection they found the "hydraulic oil tank" empty! Well it turns out that tank supplies the oil to the VHT transmission, on the rear where the filters are. The transmission is in front of that and it does not have filters. It basically is a manual trans just like in a car or truck. The two do not exchange oils! Not to make matters worse you state the hydraulic bed system runs off the "hydraulic oil tank" but that is incorrect! They told me that the bed runs off the transmission oil. Confused? Don't feel bad since they were not aware of how the system worked since these models are new to the market. They are now in discussion with Kubota to have them make good on what happened to me. They believe that the owners manual are poorly written and certainly unclear even to them. They stated to me that they very well may have made the same mistake as I did!! The bill was about $4000 $5000 is what I was told!!! I paid nothing since I am a very good customer to them. So if you change the filters they will drain the "hydraulic oil tank'" and not the transmission. Do not do what I did!! Here is my original question to the board a few days back that you may want to read. Ask me any questions you feel you need to know about Good luck!!!

http://www.nettractortalk.com/forums/showthread.php?t=16046

Hello Kubotaman:
Sorry to hear of your misfortune. The owners manual is very confusing and I can certainly understand what happened with your adventure. The manual calls for hydraulic filter changes at 50 hours, but not "transmission" fluid. That is also not clear, but if you carefully study the "service intervals" in the maintenance section of the owners manual, you will see that it calls for filter changes at 50 hours, but only at 400 hours for "transmission fluid", although it calls for "hydraulic oil tank" change every 200 hours.
Now, it's not easy to change the hydraulic filters without draining the transmission. I jacked up the back end as high as I could with my floor jack and then I lost about a pint of fluid. (estimate). When I went to check the fluid level on the transmission after replacing filters, it didn't call for any to be added, which seemed strange to me. After reading your post, I now understand why. I didn't check the hydraulic tank level which will probably indicate the need for oil. I can't check it now as the machine is at the dealer for a snow plow install. Thankyou for sharing your insight and experience with us all. Everybody out there that does their own maintenance, BEWARE. I wish there were some way to alert everyone who owns and maintains one these new machines.

After I got it back from the dealer it ran fine except it did not slow down as fast nor get to top speed. It use to get to 29 mph and now it only gets to 24mph at best. I know that the case where the pump is located was scored and I assumed that they replaced it. I now feel they did not and I believe that it is not sealing correctly to pump the necessary volume of fluid. I ordered the repair manual, $110, so I can see what is involved to replace the case. I will call the dealer to see if my suspicions are correct. I will have to deal with it when I find out.

My dealer did 50 hour service. List includes

Fuel Filter
4 qts Motor Oil
3 gallon UDT
Filter? I'd guess for the transmission but it does not say
Oil Filter
Oil Filter Cartridge

Wow, that seems like quite a change in how things are done on the New X models.

I assume the transmission also still uses UDT or SUDT.

The seperation of transmission fluid and VHT fluid must be to keep gear grindings out of the VHT, that would be my best guess.

They are not concerned about heat in the hydraullics and transmission because they don't develope as much as the VHT would. So having these together would help to keep that oil a little hotter than if the hydraulics were seperated by themselves as it was in the old models.

Loved to see the new manual.

Good luck and hopefully Happy Motoring.

Kubotaman
If they replaced the VHT, then that could have affected your top speed. My unit will only do 22 MPH on the level and I understand that is controlled by a pressure adjustment. I asked my dealer to adjust mine so I can get 25 MPH.
I'm not sure I fully understand how you destroyed your VHT. Is it that after you drained the "transmission" and then upon replacing the hydraulic filters you lost all the oil in the "hydraulic tank". Then you replaced the "transmission" oil only, but the "hydraulic tank" was empty. Is that a correct analysis of what happened?
I hope Kubota will make good on your tragedy. They bear responsibility, because the owners manual is incomplete. They could have prevented that with a couple of sentences explaining what oil served what system.
The "hydraulic tank" calls for replacement at 200 hours use. Is that typical for a VHT system?
Can anybody else add any wisdom to this discussion???

DoubleJack, your understanding is correct. When I replaced the filters for the first time I let them drain for quite a few minutes. When I installed the new filters I had no idea that the oil was being drained from the "Hydraulic Oil Tank". After having installed the filters that is when I found I had problems. I installed the old filters back and again oil was lost. To make it easy to understand after each removal of filters oil was lost and of course it is draining the oil tank!!! Well the last time I tried to move the RTV is when the VHT was scored in the casting where the pump is located. I didn't pay anything for the repair but it doesn't seem to go as fast and it certainly doesn't stop as fast using the VHT. It may be just my imagination. I know people may look at me as being careless but I followed the book which at the least is poorly written. That is why the dealer is asking Kubota to stand behind the repair. Double Jack you have to realize there is a transmission and a VHT transmission. The oils in each is not mixed at any time.

It looks like I over looked a very important point in regards to my posts. My RTV is the new X1120D. The oil change looks like it is different from the "older" 1120's. Just to let you know.

You had me worried about the VHT fluid change, plus 2 filters, I did on my 2010 RTV 900 about 50 hrs ago ( Now have 100 hrs). I went back and checked my manual and I "think" I confirmed that the VHT is separate from the auxiliary hydraulic dump system.
I've had no problems.

Is that correct ?

TRIBUTE100 said:

You had me worried about the VHT fluid change, plus 2 filters, I did on my 2010 RTV 900 about 50 hrs ago ( Now have 100 hrs). I went back and checked my manual and I "think" I confirmed that the VHT is separate from the auxiliary hydraulic dump system.
I've had no problems.

Is that correct ?

Click to expand...

YES SIR...........For us that lead a simpler life, we miss out once again on all of this new stuff..........God bless.......Dennis

Thanks Dennis,
That's why the last new vehicle I bought was a 1985 Olds Ciera, GM's beginning attempt at front wheel drive cars, and what a lemon it was. Now I try to research used cars before I buy one, and since that '85 Olds, I've been able to pay cash and not finance. Then I keep them forever. It also keeps you from buying something beyond your means.

Tribute,
It is a nervous time with all the changes to the new models.

But just remember, if it has the new suspension, it has new maintenance routines.

And the transmission end is all new too so easy to tell the difference.

"X" models and years 2014+.

Still odd that the user manual was that vague.

Shame on you Kubota!