Hydrostatic Drive Hesitation

   / Hydrostatic Drive Hesitation #1  

KevinPA10

New member
Joined
Mar 30, 2005
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7
I have been looking to purchase a Kubota L5030. I test drove one today and found that when I accelerated, especially in the high range, the tractor hesitated a fair amount. It was very difficult to keep it from hesitating and being jerky. The only way I found that would work was to "floor it" or to just use the cruise control.

For some reason, when I operate the tractor my foot on the pedal would bounce a little on the pedal. This would cause the tractor to jerk which would then make my foot bounce even more resulting in a jerkier tractor movement. If I advance the cruise control level and operate the pedal from the cruise control level, the hesitation would stop.

This seems to be a design flaw with the pedal. The dealer was familiar with the problem as was a Kubota rep who happened to be at the dealership. The dealer downplayed the hesitiation, though, and said that I would get used to it and be able to operate it smoothly.

I test drove the tractor around for a good 1/2 hour and was unable to improve the performance significantly, though. Again, this is most noticeable in the high range but I also saw it occur in the medium range.

Has anyone seen this problem? If so, have you been able to compensate for it by using a better operating technique that I seem to have?

I also test drove a JD 4720 and it did not exhibit this behavior.

Thanks!

Frustrated Almost Kubota Buyer
 
   / Hydrostatic Drive Hesitation #2  
Kevin,
My 3430HSTC acts the same way in high range. Once you get on to it you can feather the pedal and it seems to be better. They (Kubota) changed their hydro transmissions recently and they are now called feather step tranmissions and that is exactly what you have to do, feather that pedal. Remember, high range is meant to be used as a road gear and not for running on rough, uneven terrain.
I have not noticed it in any other speed ranges.

Bill
 
   / Hydrostatic Drive Hesitation #3  
I just bought an L5030HSTC and have adjusted to the pedal in 2 days (10 hours) from running a gear tractor.

High range is for the road, small pedal movements cause big tractor speed changes.

I use medium range at 1800 -2100 rpm so far for most stuff and it is as smooth as can be. You are resting your heel on the floor and not on the reverse part of the treadle right? Your leg weight rest on the floor and you just adjust your toe position.

I was skeptical as first but I am getting the hang on it quickly. My only bad habit is mashing the pedal when going to raise the loader as the normal tractor I use has slow hydraulics and I usually reved it up when raising.
 
   / Hydrostatic Drive Hesitation #4  
This is typical response for any hydrostatic type transmission, you'll get used to it and figure out the right ways to avoid it with more experience.
 
   / Hydrostatic Drive Hesitation #5  
I had the same problem on my new L3830 HST but have gotten used to it. At first I thought it was me because the problem did not occur much on pavement, but on my bumpy grass it was pronounced.

What does feathering mean in this context?
 
   / Hydrostatic Drive Hesitation #6  
philc,
When you feather a hydro pedal you ease the pedal downward as opposed to smashing it to the floor. The new hydro's are very responsive after you get the hang of it.

Bill
 
   / Hydrostatic Drive Hesitation #7  
I recently bought a used B7500 with ~140 hours. The tractor is super clean and was well kept, but I'm not sure if there's a problem with the HST. The first day I used it I noticed a pretty loud whine when the clutch is out. When I put the clutch in, the whine stops. Well, I convinced myself that this must be normal and continued to operate. The next day, I noticed that if I use go easy on the HST pedals, I would get a jerkyness. As if the drive would engage, then disengage, then engage, etc. I checked the transmission fluid and the level looks good (is it supposed to be clear?). I tried a few things to get rid of the jerkyness. What seemed to work was increasing the throttle to about 2000rpms. I had been operating at a very low idle before that. It seemed to go away, but I'm not convinced that I should have had the problem in the first place. Also, the whine is there, even at the higher throttle settings, you just don't hear it as well over the engine noise. Is there anything else I can check/adjust, or is this normal?
 
   / Hydrostatic Drive Hesitation #8  
Thanks for the definition, Bill. Sounds like a fancy term for the way I drive everything these days.....

After playing with it for a while today I think the "hesitation" experienced by myself and others is really just a very high sensitivity to the foot pedal movements. A tiny, quick movement is communicated immediately and acted upon. Thus, if any of the land surface roughness comes through to the foot, it goes to the pedal and seems amplified. The trick is to learn how to position and control your foot properly.
 
   / Hydrostatic Drive Hesitation #9  
Be sure not to put your entire foot on the pedal. Some folks don't seem to adapt or get comfortable with the superb control that HST offers. If you cannot get to where you can easily control the tractors speed without experiencing jerkiness, you might consider a different brand or go to a shuttle. I found adjusting to HST a snap and now can so easily control the tractor even in the roughest enviroment. If you ever have driven a Bobcat skidsteer, it is difficult at first to smooth out the bumps but in a short amount of time, you can control the sticks to actually smooth out the bumps like no manual transmission can. Difficult to explain, relatively easy for most folks to learn.
 
   / Hydrostatic Drive Hesitation
  • Thread Starter
#10  
Thanks for the input, but I'm just not sure that I buy it. /forums/images/graemlins/confused.gif I agree that you would normally use High for transporting the tractor, but with smooth ground I could see myself trying to use High and regulating the speed with the pedal.

I drove the tractor around the lot for quite a while and didn't seem to get better at it, and that was on a mostly paved lot.

Also, I didn't have the hesitation problem with the John Deere. I would like to buy the Kubota but this problem has definitely got me reconsidering my decision.
 
 
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