B7500 HST power steering and and 3 point lift problems in high temp.

[hwew]

juat a note which may be relievant. here in Australia, where it is quiet often over 90 deg, we dont get Super UDT, only the normal UDT. i have never seen the problems you are describing before. i wonder if they dont bring the SUDT into Australia because it cannot handle the heat.

You nailed it!!!

Regular Kubota UDT will hold up better in hot weather.

Kinematic Viscosity @ 100°C, cSt:

Kubota Super UDT---------------------------------------------9.0
Kubota UDT---------------------------------------------------9.5
Chevron Synthetic All-Weather THF----------------------------9.5
AMSOIL Synthetic tractor Hydraulic/Transmission Oil (ATH)-----9.7

The best protection for your location would be a Hydro Fluid that has a Kenematic Viscosity of 9.5 and above at 100 deg. C.

If a tractor owner lives in a location that the temp. goes from 25 deg. F. (-3.9 deg. C.) and lower. And temp. goes 90 deg. F. (32 deg. C.) and higher the best pick for an all weather Hydro fluid is the Chevron Synthetic All-Weather THF. To date I cannot find a better All-Weather Hydro Fluid.

As you see from the specs above. For locations like you. The best protection in mild temps. and very hot temps. would be AMSOIL Synthetic Tractor Hydraulic/Transmission Oil (ATH). Amsoil will give an extra margine of protection in very high temps. over other Hydro Fluids.

 

[ozzie tractor]

does anyone have any idea what amsoil is marketed as in Australia, because i have never heard of this brand before. the only thing i can think of is ampol, or is that another brand all together

 

[orangebluegreen]

Thanks for the input.


When I was first looking into what trans fluid to use I read several posts on TBN that claimed Kubota SUDT was the same as Chevrons just repackaged for Kubota. I found the synthetic Chevron close enough to me to buy but it was a bit more than SUDT at my closer dealer so I went with SUDT. Now I’m not sure the two are the same. The fluid I drained had a distinct orange color to it and was very clean, the SUDT is not as colored as what I drained, in fact almost impossible for me (mildly color blind) to see on the dipstick. It could be that the drained fluid had slightly discolored with use however.

My Kubota dealer also sells AMSOIL trans and motor oils. I use Mobil-1 in my street vehicle but I am not able to find their diesel synthetics anywhere local, made me wonder why, I’ve not called Mobil.

I need to buy a service manual and start a little poking around on the machine. I do have a parts manual. I do remember when I changed the oil filter there was a rubber hose pressing hard against it, looking at the parts breakdown it appears (without going outside and looking) to be the hydraulic pump suction hose, though I don’t remember seeing any collapse and since the trans itself does not seem to operate differently at high temps (just the steering) it would appear a steering only problem. The loader, PTO and 3pt never seem to decrease in performance either. It feels like fluid that is too thin, a relief pressure spring that goes weak at temp, or a hose collapse....the pump feels like it’s starving because the more you back off the hydro pedal their is a corresponding return to power steering, though still very rough once it gets there.


A couple other threads I found of interest:

http://www.tractorbynet.com/forums/...steering-problem.html?highlight=hard+steering

http://www.tractorbynet.com/forums/...teering-problems.html?highlight=hard+steering

 

[hwew]

Thanks for the input.

When I was first looking into what trans fluid to use I read several posts on TBN that claimed Kubota SUDT was the same as Chevrons just repackaged for Kubota.

Hello orangebluegreen,


There has been many things written about Kubota Super UDT and some are false.

Things I do know about Kubota Super UDT:
A. It is not a Synthetic Fluid.
B. It is not a repackaged Chevron product. (Chevron Rep. and I had a talk about that)
C. Specs are not as good as Chevron Synthetic All-Weather THF
D. Most of all it does not hold up in hot weather like Chevron Synthetic All-Weather THF. Run Kubota Super UDT in my B7500 and it starts having problems at 90 deg. F.

I beleive this is enough to see the two fluids are not the same.
Be carefull on what is written on this topic.

 

[hwew]

does anyone have any idea what amsoil is marketed as in Australia, because i have never heard of this brand before. the only thing i can think of is ampol, or is that another brand all together

I just sent a message to AMSOIL. I should find out in a couple days. When I do I'll send you a message.

 

[tomf]

HWEW, Just got done reading your posts. I have a b2400 that has a heat related power steering problem. After 1 to 2 hours of hard mowing the power steering goes out when I turn to the left. I've had this problem for almost the entire time since I bought it new. Based on your post I'm going to try a synthetic oil this year. I will post an update after I've tested it this summer.

One symptom I'm going to add that I did not see in any other thread is:
Once I lose the power steering, sometimes after I'm cranking the wheel hard to the left, I feel a pop and the power steering returns for a short time. Please note I did not hear a pop but I felt the pop through the steering wheel. Does this give you experts any ideas. Thanks Tom

 

[hwew]

Tom what part of the country are you in?

 

[tomf]

I live in Omaha NE.

 

[hwew]

I would look Chevron synthetic all weather THF. I believe it gets cold at your place and the Chevron would work great in Hot or Cold weather. I still no longer have power steering problems so that is a good sign.

I was in the Process of becoming a dealer for this product but the wholesaler is calling for me to purchase 55 Gallons of this stuff and then he will fill the 5 gallon buckets. That was not the deal I worked out with Chevron. So I have to start from scratch.

If you cannot get the stuff let me know I will try to help.

 

[tomf]

It does get cold here. We've been in the deep freeze for the last couple of weeks. Single digits during the day and below zero at night. Thanks for the input Tom