Why Is It Difficult To Shift Hydrostatic Transmissions

rancher1524

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I have a Kubota B3350SU and Kubota RTV-X1120D, Both have hydrostatic transmissions and both are difficult to shift between gears. Both owners manuals show steps to go through if you have difficulty shifting. Are all hydrostatic transmissions difficult to shift between gears.
 

SDT

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I have a Kubota B3350SU and Kubota RTV-X1120D, Both have hydrostatic transmissions and both are difficult to shift between gears. Both owners manuals show steps to go through if you have difficulty shifting. Are all hydrostatic transmissions difficult to shift between gears.
None of mine are but you must come to a complete stop, wait a moment, and it helps to remove one's foot from the hydro pedal. It also helps to momentarily reverse direction.

SDT
 

Roadworthy

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The hydrostatic transmission is actually a fluid type drive coupled to actual toothed gears. The ranges are selected by toothed gears. That's why you should come to a complete stop before changing ranges. The gears are not synchronized as they are in the standard transmission in a car. They're more like the gears you don't shift on the fly with a standard transmission tractor.
 

rancher1524

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Tractor LX4020 B3350SU
May 11, 2016
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Evans, Washington
I never try to change gears while moving. All I am saying is Kubota knows the hydrostatic transmission does not always change gears without trying one of the procedures they describe in the owners manual. If they know it is a problem why can't they fix it or is it a problem with all hydrostatic transmissions.
 

jajiu

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My L gear is very difficult to shift into and sometimes jumps out into N and believe me, my foot heads for the brake pedal when I'm on a hill and it does that!
 

Henro

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I change between gear ranges while the tractor is moving ever so slowly when coming to a stop, or by drifting slightly after being stopped on a slope.

No grinding or anything, just a smooth transition.

Of course, if the lever moves easily between ranges while stopped I chose the range I want and do not think twice about it.

Actually it has never been an issue for me, at least once I realized to change ranges while the gears are turning slowly.

No question that the gears sometimes want to stay in the selected position. But as I said, it has never been an issue for me personally though.
 

bearbait

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My L gear is very difficult to shift into and sometimes jumps out into N and believe me, my foot heads for the brake pedal when I'm on a hill and it does that!
Yours is not going all the way into low. After you shift it into low keep pressure on the stick while touching the peddle to go forward and you will feel it go further into low gear. Keep the rpm's low while doing this, 1000 or lower.
 

mikester

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My owners manual says come to a full stop and depress the clutch when shifting ranges between HI-MED-LOW. I find clutching helps make it easier.
 
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SDT

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My owners manual says come to a full stop and depress the clutch when shifting ranges between HI-MED-LOW. I find clutching helps make it easier.
I always clutch when changing ranges on my B1750 but neither my L6060 nor my B3350 have conventional clutches.

Still no significant issues changing ranges.

Yes, of course, if stopping on an incline, the meshed gears will have load applied making range changes more difficult. That's one reason that tractors have brakes.

SDT
 

jajiu

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Yours is not going all the way into low. After you shift it into low keep pressure on the stick while touching the peddle to go forward and you will feel it go further into low gear. Keep the rpm's low while doing this, 1000 or lower.
I agree, I do that as well, but sometimes it just pops into N. I have had it at the dealer twice and asked them to check it out, but they said they would have to pull the transmission to do it, expensive. I live with it and my foot is always on the brake pedal in case of an emergency stop is needed.
 

troverman

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I find the shifts are easiest with the tractor slightly moving. The manual says fully stopped, but this is just to cover their rears in the even someone tried shifting while moving more than slightly. The dealer recommended shifting while slightly moving.

The Grand L series that some people have in this thread has a little nicer range change lever than what you get in a standard L, standard B, or MX...I've had zero trouble changing ranges on mine.
 

bearbait

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I find the shifts are easiest with the tractor slightly moving. The manual says fully stopped, but this is just to cover their rears in the even someone tried shifting while moving more than slightly. The dealer recommended shifting while slightly moving.

The Grand L series that some people have in this thread has a little nicer range change lever than what you get in a standard L, standard B, or MX...I've had zero trouble changing ranges on mine.
Agreed, basically just at a slight roll and let it slip into gear. After owning an L3800, an L3200 and now an L3560 it all becomes second nature, don't even think about it, just do it.
 

dirtydeed

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one additional trick if convenient is to lift the weight off the front wheels with the loader. Sometimes, just a slight weight reduction is needed, other times (when 4wd is engaged) lifting them off the ground completely will allow you to shift without any issue.
 

TiggerToo

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Kubota B2650, snow blower, back blade, FEL, land plane
May 14, 2016
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I have a B2650 and shifting between ranges is not the best. Always find myself playing with the lever, the brake and hydro pedal to get into H-M-L . Have never had it pop into neutral on its own yet.


Sent from my iPhone using Tapatalk
 

jajiu

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Exactly what he said. A quick tap of the reverse pedal and it slides in like butter.
I do that too, but like I said before, not always but it does pop out into N on its own, especially when going down hill, WOW! My foot is always on the brake pedal in case it is needed.
 

lugbolt

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The RTV-X diesels have a release. You push the brake pedal down firmly, and while you do, the cable that's attached to the brake pedal pulls a release lever on the HST which relieves pressure, easing the shifting effort. They ain't always adjusted perfectly due to normal wear & tear, etc, so if you're having issues with it grab your work shop manual and thoroughly review the cable adjustment procedure. If you get it too tight, it will be a total slug that won't pull in LOW gear much less in high (remember it releases pressure in the HST...).

It works slick as long as everything's adjusted properly.

And therein lies a second "problem". The gears that mesh are cut such that they are very strong for their intended usage, but the downside is that their shift "dogs" (and rings) do NOT let go of each other if there is any pressure on them. If the gears (and dogs/rings) were cut differently to make it easier to shift to/from gear, they wouldn't stay in gear while in operation; which is a whole separate problem.

IMO, ditch the HST crap and put either a real automatic transmission in it, or a manual shift 4 speed with low range. BUT since 96% of Americans (and probably similar worldwide) can't drive a manual, there would likely be a whole lot of clutches being replaced.
 
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troverman

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...IMO, ditch the HST crap and put either a real automatic transmission in it, or a manual shift 4 speed with low range. BUT since 96% of Americans (and probably similar worldwide) can't drive a manual, there would likely be a whole lot of clutches being replaced.
HST is actually a pretty clever system with few moving parts to wear out and the ability to move very heavy loads. A torque-converter automatic is likely heavier and has a lot more moving parts to wear out. A manual would be OK in a side by side (although more difficult to get up and over certain off road obstacles) but in a tractor it is less efficient if you change directions and speeds a lot.

You'll find Europe still has a lot of manual transmission drivers. My last truck was a RAM 3500 dually with a diesel and a stick. I enjoy driving the stick, but it simply isn't as good when towing is involved. If you are pulling a heavy gooseneck trailer and try to climb a hill in 4th gear, only to realize halfway up that the engine can't maintain speed in that gear...you have to change down into 3rd gear. Well, changing gears takes a couple of seconds. Not only do you lose speed, more importantly you lose turbo boost. By the time you are in 3rd and foot to the floor, you may find you are already too slow for 3rd and now need to drop to 2nd gear. My current rig is a 2019 RAM diesel and they dropped the manual trans starting in 2019. If the auto needs to downshift on a hill with a heavy load, the change is nearly instantaneous and virtually no boost is lost. This new truck does have 1000lb-ft which is significantly more than the old truck, but nevertheless it pulls hills in an amazing way.

All of that has nothing to do with HST transmissions, sorry for getting off course.
 

nbking

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I do that too, but like I said before, not always but it does pop out into N on its own, especially when going down hill, WOW! My foot is always on the brake pedal in case it is needed.
Mine did that one time, popped out of medium going downhill on my gravel road, scary ride. I have no problems shifting my tractor, but my rtv is another story, it can be a true pain in the butt, it's been the same since day one, and my dealer said it would get easier over time, as everything started wearing in. Lol definitely creeping, or mashing on the brake helps with the shifting.
 

ItBmine

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My B 2620 was very hard to change ranges when it was new also. But it got way better by the time I got over 500 hours. And as others have said, when it doesn't want to shift I just push the forward then reverse pedal while it is in neutral and then it goes easily.

I have also found (my B has a clutch pedal) mine shifts easier if I do not depress the clutch. I only do it fully stopped, not moving. But for some reason it goes easier without the clutch.