BX25D slow speed and lack of HST power

[PoolGuy]

Greeting-

I purchased a used BX25D a few weeks back. 330 hours. The implements work great at partial and full RPM. However the forward speed is slow... maybe 4-5 MPH. I think the reverse speed is also slow, but I don't have a good frame of reference as to what it should be. At partial RPM, you really have to smash the pedal to get er' to go forward. I was working on a sloped driveway today, maybe 10-12% grade, cleaning the ditch. When I started to go back up the hill, the BX25D could not even get moving in rabbit gear. The engine whined hard, but the tractor refused to get moving. I needed to use turtle gear, which s l o w l y got me back up the hill. My little BX2200 runs this hill in high gear without issue.

So I Googled it...

+ Checked the HST linkage - the nut is on, tight, and everything appears straight and solid with full travel to stops.

+ Checked the trans oil - a spec high on the stick, maybe 1/8" above the cross hatch. Looks very clean.

+ Engine seems to have good RPM and power. Runs great. Good power to implements.

+ It almost feels like when you try to move a BX with the parking brake set. So I checked the parking brake. Nope. Wheels spin free when elevated and in neutral.

So what's next? Do I have some severe internal HST issue?

Also of note, but probably not related. The HST pedal is very slow to return to the neutral position. Take your foot off the pedal and she keep going for another 10-20' as the pedal slowly makes its way back to neutral position. Same in reverse. I tried adjusting the return spring, but this did not seem to help. I have not greased it yet, which is my next step. I find myself riding the forward and reverse pedals (toe and heel) to control the tractor. My main concern though is the forward speed/power issue.

Thank in advance for reading this long post and any knowledge which you may be able to share.

 

[jkcolo22]

Greeting-



I purchased a used BX25D a few weeks back. 330 hours. The implements work great at partial and full RPM. However the forward speed is slow... maybe 4-5 MPH. I think the reverse speed is also slow, but I don't have a good frame of reference as to what it should be. At partial RPM, you really have to smash the pedal to get er' to go forward. I was working on a sloped driveway today, maybe 10-12% grade, cleaning the ditch. When I started to go back up the hill, the BX25D could not even get moving in rabbit gear. The engine whined hard, but the tractor refused to get moving. I needed to use turtle gear, which s l o w l y got me back up the hill. My little BX2200 runs this hill in high gear without issue.



So I Googled it...



+ Checked the HST linkage - the nut is on, tight, and everything appears straight and solid with full travel to stops.



+ Checked the trans oil - a spec high on the stick, maybe 1/8" above the cross hatch. Looks very clean.



+ Engine seems to have good RPM and power. Runs great. Good power to implements.



+ It almost feels like when you try to move a BX with the parking brake set. So I checked the parking brake. Nope. Wheels spin free when elevated and in neutral.



So what's next? Do I have some severe internal HST issue?



Also of note, but probably not related. The HST pedal is very slow to return to the neutral position. Take your foot off the pedal and she keep going for another 10-20' as the pedal slowly makes its way back to neutral position. Same in reverse. I tried adjusting the return spring, but this did not seem to help. I have not greased it yet, which is my next step. I find myself riding the forward and reverse pedals (toe and heel) to control the tractor. My main concern though is the forward speed/power issue.



Thank in advance for reading this long post and any knowledge which you may be able to share.

Try this first: https://m.youtube.com/watch?v=hTtSPcAEJY8

Did you grease the little zerk fitting under the floor mat?

Also make sure your brake pedal is easily returning to neutral position. This guy had an issue with a sticky brake pedal linkage that fried his rotors (and ultimately Kubota denied the claim). The fact that the engine whines but the tractor doesn’t move makes me wonder if you have a similar issue. And quit riding the brake pedal! The brake on an HST is for stopping the tractor, not slowing it down! https://r.tapatalk.com/shareLink?s...m/forums/showthread.php?t=406460&share_type=t



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[PoolGuy]

jkcolo22-

Thanks for our reply. The YouTube link takes me to the "missing linkage nut" problem. I was really hoping that was my problem, but the HST linkage has been inspected and appears AOK.

The engine tries to get the tractor moving up hill when I crush the forward pedal (high gear). The engine does not really "whine". You can just hear it trying to build up the hydraulic pressure and is under load. It is like the brakes were applied. But if I take my foot off the forward pedal, the tractor rolls backward down the hill. I don't think the brakes are the problem. It just "feels" that way.

Is this normal? Shouldn't a BX25D get going (in high gear) on a slight grade?

 

[jkcolo22]

jkcolo22-



Is this normal? Shouldn't a BX25D get going (in high gear) on a slight grade?

No and yes. I’ll keep thinking on it. Hopefully some of the smarties jump in today.

I’m thinking it’s something on your list but you missed it. That or you’re really unlucky and have a very unique problem.


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[85Hokie]

jkcolo22-


Is this normal? Shouldn't a BX25D get going (in high gear) on a slight grade?

Define your slight grade....

My BX25D will NOT go up a "grade"....like 15 degrees in high gear.....nope - not happening.... dont care if I ease off the pedal or smash it to the floor. It is simply too much weight going up the hill. Now - flat ground, it will haul ass and take names......

Low range it seems to climb a mountain!

 

[jkcolo22]

Define your slight grade....



My BX25D will NOT go up a "grade"....like 15 degrees in high gear.....nope - not happening.... dont care if I ease off the pedal or smash it to the floor. It is simply too much weight going up the hill. Now - flat ground, it will haul ass and take names......



Low range it seems to climb a mountain!

He estimated 10-12%. That shouldn’t be enough to completely keep it from moving. I agree though, steeper grades and high gear isn’t going to get you anywhere. He also said his top speed is the the 4-5mph range. That is also suspicious.


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[85Hokie]

He estimated 10-12%. That shouldn’t be enough to completely keep it from moving. I agree though, steeper grades and high gear isn’t going to get you anywhere. He also said his top speed is the the 4-5mph range. That is also suspicious.


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Missed that in my hurry......I have a 20% grade that I have to go up....backwards in low gear, the RPM drops too.

I go up a 300 foot dog leg left when coming up the rear of my house, grade changes from flat to 5% to 10% to about 15%.....I can get about to the 10% grade and she'll slow down and stop in HIGH range, moan and groan - shift to low and off we go!

 

[jkcolo22]

OP: What kind of surface is this? And have you checked air pressure in your tires?


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[RCW]

Since you just bought it, I suggest changing HST Fluid and filter, unless you know definitively it has decent Kubota SUDT2 fluid in it. Then you also have a baseline for future service. In a BX25D, I would not use anything other than SUDT2, or a high-end SUDT2-compatible product like an Amsoil version.

It's amazing what some guys will fill one with...especially when selling it. Universal stuff from a 5 gallon pail from TSC isn't good, and will damage the HST in time. Several guys here have learned it the hard way...

If you're good with HST fluid, the pedal is not like a gas pedal on your car or truck. "Mashing" the pedal in high range will work against you. Low range and an "easy" pedal will provide much more torque to the wheels. Get it rolling with the pedal, and just keep easing into it...Trust me, I'm not being a wise-apple, it comes up here quite often...

Not saying either are the causes, but it's where I would start.


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[sheepfarmer]

Besides the suggestions on the power issue, get a shop manual and fix the pedal not returning to neutral issue. It is not normal for the tractor to keep going when you take your foot off the hst pedal, and it is a safety issue. Maybe the adjustment for that will help your power problem

 

[RCW]

Besides the suggestions on the power issue, get a shop manual and fix the pedal not returning to neutral issue. It is not normal for the tractor to keep going when you take your foot off the hst pedal, and it is a safety issue. Maybe the adjustment for that will help your power problem

You bet. Sheep has a great point I omitted. There's a pedal damper that sometimes causes issues with the pedal retuning to neutral position. Always start with the simple stuff.

WSM can probably be had here:

http://www.kubotabooks.com/

 

[jkcolo22]

You bet. Sheep has a great point I omitted. There's a pedal damper that sometimes causes issues with the pedal retuning to neutral position. Always start with the simple stuff.

WSM can probably be had here:

http://www.kubotabooks.com/

Or just watch this. From the living, breathing WSM. https://youtu.be/FdEq4pqFb5I


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[sheepfarmer]

Yes!! Paul Short aka Wildfire to the rescue! I knew that stopping issue sounded familiar!

 

[jkcolo22]

Yes!! Paul Short aka Wildfire to the rescue! I knew that stopping issue sounded familiar!

Somebody should make an index of his videos. I had to dig around to find this. His titles are not the most convenient way to find things!

OP: This video also gives you a good idea of how fast your tractor should move!


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[PoolGuy]

First off, I am impressed with all the swift posts of ideas and suggestions for me. WOW. Thank you all for taking the time!

Here are my next steps... hopefully today... based on all of your feedback:

- Grease the zerk fitting on the HST pedal and see if that speeds up pedal return-to-neutral time.

- Adjust the HST pedal damper (thanks JACOLO22 "From the living, breathing WSM. https://youtu.be/FdEq4pqFb5I")

- Further adjust (tighten) the HST pedal return spring. I did this some yesterday, but I will tighten further if the first two things do not solve this problem.

- Once I have the tractor stopping in a reasonable amount of time after taking my foot off the pedal, I will see if this problem was somehow related to my speed/power issue.

- Check tire pressure.

- I will also measure top forward speed and measure the grade on the "hill" I was trying to climb in high gear so that I have more quantitative data to share.

By the way, the "hill" is my driveway. It is hard packed road gravel.

12 degrees F outside this morning here in Wisconsin. Not good "crawling under the tractor" weather.

Thanks again. More to follow.

 

[jkcolo22]

First off, I am impressed with all the swift posts of ideas and suggestions for me. WOW. Thank you all for taking the time!



Here are my next steps... hopefully today... based on all of your feedback:



- Grease the zerk fitting on the HST pedal and see if that speeds up pedal return-to-neutral time.



- Adjust the HST pedal damper (thanks JACOLO22 "From the living, breathing WSM. https://youtu.be/FdEq4pqFb5I")



- Further adjust (tighten) the HST pedal return spring. I did this some yesterday, but I will tighten further if the first two things do not solve this problem.



- Once I have the tractor stopping in a reasonable amount of time after taking my foot off the pedal, I will see if this problem was somehow related to my speed/power issue.



- Check tire pressure.



- I will also measure top forward speed and measure the grade on the "hill" I was trying to climb in high gear so that I have more quantitative data to share.



By the way, the "hill" is my driveway. It is hard packed road gravel.



12 degrees F outside this morning here in Wisconsin. Not good "crawling under the tractor" weather.



Thanks again. More to follow.

Good luck!


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[PoolGuy]

Status:

- HST pedal Zerk fitting greased - no change
- HST pedal damper checked/adjusted - The damper was set to max dampen. I set completely to the other end, minimum dampen, with high hopes. The pedal returns to neutral faster, but still pretty unacceptable.
- HST return spring adjusted. This was quite a PITA to do. I ended up removing the spring completely to adjust the upper nut. It is now about 90% of the way to fill tight. Between this and the damper adjustment, the tractor now stops in a reasonable amount of time after your foot is removed from the pedal. Yeah! One problem solved.

On to the main problem... lack of forward speed/power:

- Check tire pressure. Yup, I have a front flat. Brought all four up to 22psi.
- Measure forward speed on flat hard pack surface after a good warm-up. The best I can get is about 5.5MPH, and it slows to about 3-4MPH on even the very slightest incline.

Is this normal? Any other ideas?

 

[sheepfarmer]

What gear range are you in? Assuming yours is like mine with a lever that chooses Low M and High? Or do you just have a lever that chooses as you mentioned turtle and rabbit?

In any case in the front of your owner's manual there should be a table that lists the max speed in each gear range.

Glad you are making progress!

 

[PoolGuy]

I am in high gear.

Owners manual says 8.1MPH in high gear. So the question is, why can I only get 5.5MPH and why my perception of not much HST power? Forward speed slows on slightest incline.

 

[jkcolo22]

I am in high gear.



Owners manual says 8.1MPH in high gear. So the question is, why can I only get 5.5MPH and why my perception of not much HST power? Forward speed slows on slightest incline.

What is your altitude?


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