So sight glass is just white - L2501/HST

[Forvols]

I have had my L2501/HST/4WD setting on flat concrete at my basement driveway for a week. Waiting on rain to pass over to do a light install and other projects got in the way. Today I peeked at the tranny sight glass(hump in the middle of floor pan, sight glass on drivers side) its just white no oil visible..guessing its low. Recommendation for hyd oil to top off?

UDT or SUDT-- I think the manual says UDT (I will verify), but dealer was pushing no..you need to use SUDT (this was discussions when I was buying the tractor)

 

[RCW]

I think UDT is out for your new HST tractor.

I think you're looking at SUDT or SUDT2. (semi- or full-synthetic)

There have been some discussions here on what fluid tractors are shipped with. My recollection is HST are shipped with at least SUDT, and maybe SUDT2. Maybe others' memories will be better.

I believe all 3 are compatible, but I would try to match what came in the tractor.

My little BX probably "burped" in the first hour, and was a quart low. My dealer gave me a gallon jug of SUDT2 to top it off. Stayed with it since, and it really quieted the HST down at the 50 change I did. (another hot topic - change or not change fluid at 50 hours)

CAUTION: I never dealt with the sight glass on a Kubota, but since the fluid is SO CLEAR, guys don't see it, and tend to overfill the HST.

The SUDT2 jug I have for my spring change:

 

[Blondie70]

I found out that if you start the engine and move the hydraulics a few times.....if the oil if overfull, you will see some little bubbles and know there is oil there. You will see the oil swirling around just a bit.
My oil rises as the tractor is operated. It settles down once it cools off. It doesn't take much to get it into the middle of the siteglass if it is just below it. Kinda a pain to drain out too much, tho....
I let mine sit overnite then added a bit of oil to get it EXACTLY in the center of siteglass....anal, huh ???? ha ha
Good Luck

 

[gs1s]

So I’m guessing mine is overfull since the sightglass is yellow. Going to try to drain some tomorrow - any suggestions on where to drain so as to not lose all of it? Worried about the drain plug and overflowing my drain pan. .May crack the filter on the sightglass side so I can watch the level as it drains. Or try to get an extractor into the fill port the rear.

Backstory - bought the tractor used with 29 hours in the spring. Immediately noticed a hydraulic leak from the block that distributes up to the loader connections. Fixed the culprit o-ring and lost some fluid in the process. Likely overfilled then when topping up. Did 50 hour service today and lost fluid when changing filters. Added fluid slowly thinking perhaps the plastic had yelllowed but never saw fluid level pass thru the sightglass. Guessing I’m now way overfull.

 

[Russell King]

Can you remove the sight window and let it drain to the bottom of that hole?

Then you will know where the fluid level is at exactly. May have to clean up some mess but you might be able to get a form-a-funnel involved to protect some of the stuff that is below that hole

 

[gs1s]

So I’m guessing mine is overfull since the sightglass is yellow. Going to try to drain some tomorrow - any suggestions on where to drain so as to not lose all of it? Worried about the drain plug and overflowing my drain pan. .May crack the filter on the sightglass side so I can watch the level as it drains. Or try to get an extractor into the fill port the rear.

Backstory - bought the tractor used with 29 hours in the spring. Immediately noticed a hydraulic leak from the block that distributes up to the loader connections. Fixed the culprit o-ring and lost some fluid in the process. Likely overfilled then when topping up. Did 50 hour service today and lost fluid when changing filters. Added fluid slowly thinking perhaps the plastic had yelllowed but never saw fluid level pass thru the sightglass. Guessing I’m now way overfull.

Update - warmed the tractor up and loosened (didn't remove) the larger of the two hydraulic filters (clutch side on my L2501) with a drain pan underneath. Once oil was flowing I went to the other side and watched until the level came down into sight glass, then ran back around and retightened the filter. I was probably a gallon overfull but this worked fine to bring it down.

Now I know that the sight glass is clearly white when empty and yellow when full.

 

[gs1s]

Can you remove the sight window and let it drain to the bottom of that hole?

Then you will know where the fluid level is at exactly. May have to clean up some mess but you might be able to get a form-a-funnel involved to protect some of the stuff that is below that hole

I considered this but given the location of the sight glass (recessed between the floorboard and the small "transmission hump"), I had no confidence on getting tools in to remove and reinstall.

 

[Evad]

Curious, but does the Super UDT2 stay clear forever? Or does it become opaque over time?

 

[SonofOrange]

Curious, but does the Super UDT2 stay clear forever? Or does it become opaque over time?

Kubota told me that the fluid should be clear, it might darken, but it should be clear. If it's getting dark or you can't see through it at all, you've got impurities in your fluid. That means that you are on the way to pump and drive failures. White usually means water.

 

[Ted1]

I think UDT is out for your new HST tractor.

I think you're looking at SUDT or SUDT2. (semi- or full-synthetic)

There have been some discussions here on what fluid tractors are shipped with. My recollection is HST are shipped with at least SUDT, and maybe SUDT2. Maybe others' memories will be better.

I believe all 3 are compatible, but I would try to match what came in the tractor.

My little BX probably "burped" in the first hour, and was a quart low. My dealer gave me a gallon jug of SUDT2 to top it off. Stayed with it since, and it really quieted the HST down at the 50 change I did. (another hot topic - change or not change fluid at 50 hours)

CAUTION: I never dealt with the sight glass on a Kubota, but since the fluid is SO CLEAR, guys don't see it, and tend to overfill the HST.

The SUDT2 jug I have for my spring change:

I have a similar question about UST and UST2 fluid compatibility.My Kubota dealer told me that you can mix UDT and UDT2 together. I wondered if that was the case. Also, I think I may have overfilled my L2501 with hydraulic fluid after a cylinder leaking. Got that fixed, but fluid was low, and added UDT2 fluid. I can see the UDT fluid in the glass window, very poor design, but I cannot tell if there is clear UDT2 on top of it or if my level is now good. I would think they would mix together fine and blend the color of each but I am not sure. Any ideas?

 

[airbiscuit]

Put this in

 

[North Idaho Wolfman]

I have a similar question about UST and UST2 fluid compatibility.My Kubota dealer told me that you can mix UDT and UDT2 together. I wondered if that was the case. Also, I think I may have overfilled my L2501 with hydraulic fluid after a cylinder leaking. Got that fixed, but fluid was low, and added UDT2 fluid. I can see the UDT fluid in the glass window, very poor design, but I cannot tell if there is clear UDT2 on top of it or if my level is now good. I would think they would mix together fine and blend the color of each but I am not sure. Any ideas?

Yes you can mix UDT and SUDT2 but you really shouldn't if you have an HST tractor, you should be running straight SUDT2.
Mixing they they will combine to the golden color and will not remain clear.

 

[Ted1]

Yes you can mix UDT and SUDT2 but you really shouldn't if you have an HST tractor, you should be running straight SUDT2.
Mixing they they will combine to the golden color and will not remain clear.

Thanks for the reply. Our 2501 is not HST but the old-style shift. It's hard to understand why they ever put a little glass window to determine fluid level.

 

[airbiscuit]

That red hydraulic fluid dye makes it a lot easier to read.

 

[North Idaho Wolfman]

Thanks for the reply. Our 2501 is not HST but the old-style shift. It's hard to understand why they ever put a little glass window to determine fluid level.

They have done it for years, as do a lot of other tractors and equipment.
Add a little dye and it will help you a lot.

 

[The Evil Twin]

Kubota would make some money selling Orange oil dye.

 

[jimh406]

I added John Deere dye to mine. Go Vols!

 

[Runs With Scissors]

I added the JD dye as well.

Makes it way easier to check the fluid.

 

[McMXi]

Here's the sight glass on the first MX6000 I owned, and this was at 10 hours or so on the new tractor, so before the 50 hour service.

Here's the sight glass on the current MX6000 at over 250 hours on the original hydraulic fluid, so after the 50 hour and 200 hour services. Looks to me like the hydraulic oil didn't change much in color over 250 hours of use. I need to pour a little fresh Super UDT2 fluid into a jar and see what the color is against a white background.

I prefer the sight glass on the MX to the dipstick on the M. I "carburized" the end of the dipstick so that I can see the fluid level. With the original dipstick and clear hydraulic oil it was very hard to see the level.

 

[The Evil Twin]

Found some orange dye for mineral oil. Not sure if it's suitable for use in a synthetic oil.