BX-24 Sub-compact hydrostat noise at 5000 hours

[bcavender]

Need some experienced opinions here.

I bought our BX-24 with loader, belly mower, 4' tiller and backhoe about 7 years ago. It was a lightly used machine and it performed quite well. Now the machine is up to about 5000 hours with 95% of it work simply belly mowing around the farm. It has always be garage kept and definitely not been abused.

The issue I have is that this year there is a much higher amount of transmission whine in all gears. Didn't have that in the first 5-6 years and it has become so loud that it is easy to hear above engine and mower noise WITH ear protection in. I have replaced the hydrostat oil with Kubota brand/spec fluid twice including filters ... once recently and it makes zero difference.

We really like this machine, no complicated electronics, easy to work on and performance is just as good as ever, but I am concerned whether or not this noise is an indication that the tranny is about to fly apart on me and I need to sell it before it lays down ... or this is just an artifact of old BXes and this series of machines, though noisy, just keep on running and easily hit 8-10,000 hours with out failure.

Cash is tight and the idea of putting it into a major tranny rebuild and still have a 5000 hr tractor or have to rebuild then buy another machine a few years later is keeping us up at night.

Anyone here experience with (a) BX transmissions failing after 5000 hours or (b) should I just ignore the noise and just keep the fluid good as these things just keep on truckin' forever?

All opinions and advice welcome and appreciated!

Bruce

 

[Grandad4]

More information about what the BX is doing might be helpful:
- Screeching noise whenever engine runs, whenever moving, or what?
- Constant pitch and loudness or depends on engine speed, ground speed or ?
- Also, can you be a little more specific about what hydraulic fluid is in the tractor? And you've only replaced the fluids twice over 5,000 hours?
- How hot do the hydraulics get when you are running it? Overheating is a sign of wear/damage.

 

[sea2summit]

Sorry I'm no help but congratulations on 5k hours on a BX! That's a lot of seat time in one.

 

[DMW]

2 fluid changes in how many thousands of hours? It may just be worn out.

 

[bcavender]

More information about what the BX is doing might be helpful:
- Screeching noise whenever engine runs, whenever moving, or what?
- Constant pitch and loudness or depends on engine speed, ground speed or ?
- Also, can you be a little more specific about what hydraulic fluid is in the tractor? And you've only replaced the fluids twice over 5,000 hours?
- How hot do the hydraulics get when you are running it? Overheating is a sign of wear/damage.

Grandad4,

Thank you for the response. Good questions.

I would describe the noise as a lower, medium pitch than a higher pitched fingernail screech and it only happens when the tractor is moving, not related to engine speed. The whine is slightly more pronounced in high gear. No whining when raising the loader or moving the hoe controls.

Morning caffeine isn't helping me like it used to. I screwed up. Let me do better on the hours. When I tried to read the hours early this morning, the LCD powered up with 6 digits with most of the tiny LCD screen blacked because of the cold, so I was guessing at what the digits were (further complicated by my crappy eyesight). I took the tractor out of the garage and let it warm up in the sun for a hour and the display was still pretty flaky, but if I press just the right way on the dash module, the reading the LCD cleans up somewhat and when the engine is running it reads 2120 hrs ... except the tens digits would click around and vary 1-5 counts ... so I really don't 100% trust it ... but figuring over the seven years we've used the tractor, 2100-2200 hrs works out to about 12 hours a week on average which is probably darn close to an honest read based on our spring-fall mowing usage.

Fluid is Super UDT2 ... and, mea culpa, I had to go searching on the spec for mfgr replacement interval ... and was shocked to see they want it replaced every 300 hours! Yikes. I had it two years and replaced the HST fluid/filter and it was clean as a pin. Repeated that about three years later, nice and clean again. So I have been doing 600-700 hrs on the fluid and am due now.

The how cylinders are warm to the touch with some use, but I haven't detected any overheating.

Clearly I need to get my act together ...

 

[zoltanthegypsy]

IIRC my '24 shows engine hours briefly when the key is turned on, but once running shows engine RPM.

Maybe get the display warmed, turn the machine off, then back on again.

Z.

 

[5030]

The fluid rarely gets 'dirty' unless it's gets contaminated with water, then it turns milky. What happens is, it looks fine clear fluid) but the additive package is shot and that especially holds true with a hydrostat because of the 'shear' action in the hydro swash plate pump.

I'd say your hydro is probably about used up from lack of timely fluid changes.

Think I'd be offing it before it gets worse or fails entirely.

 

[Grandad4]

I'm thinking along the same lines as 5030. These modern small tractors use hydraulics for just about everything... very different from old school equipment. Keeping the hydraulic fluid fresh and clean becomes really important.
You might want to do a fluid change to see if it helps. No guarantees either way.

 

[diesel85]

With proper care, the BX transmission should last 10-12k hours. The swash plate tolerances are likely low from wear, and that is why your are getting the ultrasonic/high pitch noise. This is actually considered cavitation.