hydrostatic heat and whine

[rick480]

I have just purchased a BX1860, had about 70 hours on it and was in great cosmetic shape. Everything seems to work fine, but the hyrostatic drive whines quite loudly, is that normal? Also it gets very hot after a hour of mowing, can't touch it. Is that normal? I have checked the fluid level and changed the filter.

Thanks for your help.

 

[bp fick]

I have just purchased a BX1860, had about 70 hours on it and was in great cosmetic shape. Everything seems to work fine, but the hyrostatic drive whines quite loudly, is that normal? Also it gets very hot after a hour of mowing, can't touch it. Is that normal? I have checked the fluid level and changed the filter.

Thanks for your help.

You've replaced HST makeup fluid with ????? Super UDT?
You have checked the little white cooling fan? All blades in tact?

 

[rick480]

The manual says to replace the filter and clean the screen at 50 hours, didn't know if that had been done so I changed the filter. Are you saying the original fluid is not Super UDT? When is it supposed to be replaced? Haven't seen a fan, have to look, can you tell me where it is located?

 

[bp fick]

Yes, the fluid is super udt and super udt is best for whine issues.
You used the correct Kubota filter, I assume? You cleaned the screen?

The white fan is located under your tractor. Imagine looking up, toward your seat in the back. It is in the front of the HST, pointing toward the engine.

DO NOT have your engine running when checking this fan.

 

[gwdixon]

Someone may have done the 50 hour HST oil change with cheap oil. Sometimes the smaller tractors are sensitive and almost require the expensive SUDT. Fortunately, it does not have a large capacity. It should be running like a top at only 70 hours.

If the HST makes more noise when hot then the oil is suspect.

If the fan is OK it might be worth a try to replace the hydraulic oil with SUDT, change the filter (again), and clean the screen

 

[CHDinCT]

Agree with BP on whine possibly due to a lower grade hydraulic oil. Since you don't know if the fluid was changed or with what fluid if it was, I would do a full service on the HST - new fluid and filter. They all whine some, particularly if you're using it hard in high gear at low RPM. If the pump is not making enough pressure for whatever task you're doing, you'll get more whine.

What conditions are you mowing in and how fast? Any chance you're cutting thick, tall grass at a relatively fast speed in high range? Let us know how you make out.

 

[bp fick]

My boys and I are agreed. Let me tell you my story. Got a couple of them.

When they delivered my BX1860 it whined horribly!!! Dealer said I'd get used to it. No way. One day I found some drip marks on my shop floor. The value of parking your tractor on clean cement floor cannot be underestimated. Tracked down a finger lose hydro fitting. I was livid. That shouldn't have passed QC at Kubota. Anyhow, tightened it myself. I reported it to both Kubota and my dealer.

Noticeably quieter!!! Hurrah.

Fast forward to this early spring. I added a FEL to my tractor. I had to add about two quarts of fluid to bring it up to snuff. In the excitement, I forgot, (my bad), to pick up some SUDT when picking up the FEL. Grabbed some generic premium TSC fluid that "meets Kubota udt specs". Thought to myself, "it'll be ok, it's only a couple of quarts out of almost 4 gallons. WRONG!!! That son-of-a-gun foamed and whined like an over tired 3 year old. Dang it.

Stopped by Kubota, picked up 4 gallons of SUDT and changed the entire system out. Cleaned the screen too. You know what's next!! Silky smooth, quiet as ever can be expected, and no foam. Yup, big believer in SUDT. I'm good now for a couple hundred hours.

 

[rick480]

Just cutting fairly normal length dry grass in low range fairly slow at 1/2-3/4 throttle. I notice the whine most when going down the drive or road in high at top speed with the mower disengaged. Almost deafening. Then I noticed how hot the HST got and got concerned. I'll do a fluid change with Super UDT and see if that helps. Thanks for the advice.

 

[bp fick]

Just cutting fairly normal length dry grass in low range fairly slow at 1/2-3/4 throttle. I notice the whine most when going down the drive or road in high at top speed with the mower disengaged. Almost deafening. Then I noticed how hot the HST got and got concerned. I'll do a fluid change with Super UDT and see if that helps. Thanks for the advice.

And do check that fan!!!! If you've lost some blades, it will absolutely cause overheating!!!

 

[dex3361]

Have you checked the brakes to see if they are dragging?
How about the 3 PH lift if it is left in the up position(I know it is supposed to kick to neutral but a lot don't)it will get hot because it is bypassing through the relief valve. Just a few thoughts.

 

[rick480]

And do check that fan!!!! If you've lost some blades, it will absolutely cause overheating!!!

Fan looks fine.

 

[rick480]

Have you checked the brakes to see if they are dragging?
How about the 3 PH lift if it is left in the up position(I know it is supposed to kick to neutral but a lot don't)it will get hot because it is bypassing through the relief valve. Just a few thoughts.

How would I check for dragging brakes? I do normally leave the 3 pt lift in the up position.

 

[crbr]

How would I check for dragging brakes? I do normally leave the 3 pt lift in the up position.

Make sure the brake isn't set and you have overlooked that. I do it from time to time on mine. Too bad Kubota did not put a brake set light on their machines.

 

[rick480]

Make sure the brake isn't set and you have overlooked that. I do it from time to time on mine. Too bad Kubota did not put a brake set light on their machines.

Mine won't hardly move with the brake set.

 

[bp fick]

We are referring here to the parking brake set. That little metal hook at your left foot. Frankly, my "parking brake" holds my tractor virtually dead still. But do check it just in case.

Good news on your fan!!! Believe me!! About the only thing left is:

1. Fluid in HST in not sudt. Fix: drain and fill with sudt.
2. Wrong HST filter. Fix: install correct HST filter. If you are absolutely confident you installed the proper filter, then empty, drain and re-install when you re-fill with sudt.
3. A line leak somewhere. This is your last check off, imo.

Finally, high range (rabbit) always produces a bit more whine than low (turtle) range.

 

[bp fick]

Clean the screen too! Since you are likely heading for a complete dump and re-fill, just to be sure.

Question. You said you changed the hydro filter? Was the filter you took off grey painted, or was it white?

 

[dex3361]

How would I check for dragging brakes? I do normally leave the 3 pt lift in the up position.

The BX1500 I have will let the lift handle stay in the up position and it squeals and bypasses I have to physically put it in the middle neutral position.

If the brakes do not feel right the may be sticking and if you happen to leave the park brake locked lightly applied it will squeal and get hot.

 

[dex3361]

I agree that the wrong fluid and a dirty filter will the same symptoms.

 

[bp fick]

The BX1500 I have will let the lift handle stay in the up position and it squeals and bypasses I have to physically put it in the middle neutral position.

My BX1860 does not have that "feature".

 

[dex3361]

My BX1860 does not have that "feature".

I think the BX1500 is not supposed to be that way. If I have my hand on the lift lever and it goes to the top I can feel it try to trip to neutral but it will not quite do it.