YT359 Transmission

[presnewt]

Can someone explain the HMT transmission on this tractor. From what I understand it is not the same as an HST and it delivers more HP than the HST. I have asked a couple of people at Yanmar and have looked for some videos but I cannot figure out how it actually operates compared to a shuttle shift or HST. I have seen videos of Hst that uses no clutch, some that use clutch for gear changes but not fwd/ reverse but I am not sure about this one. They say it has a shuttle shift lever on the steering column but does it also have a foot pedal for power. When does the clutch come into play. It seems a little complicated especially compared to HST that has a foot pedal for forward and reverse but nothing on the column to worry about. All I have ever driven is the old time tractors that use clutch for everything and a subcompact that has no clutch and just a foot pedal.

 

[Andy64]

I have a YT359C and before that I had a kubota with Hst. The Yanmar has a shuttle shift on the steering column for forward and reverse, power comes from a pedal just like the gas pedal in your automobile. You press the pedal to move forward and if you want reverse you simply ease off the pedal, switch to reverse and press the pedal again. With practice you can do this without fully letting off the pedal and it does work extremely fast. The major difference in the Yanmar verses a hst is that the Yanmar works very similar to the older tractors you are use to. On an hst, once you lift your foot from the pedal the tractor stops, on a Yanmar if you totally lift your foot from the pedal the tractor will continue to “creep” either forward or backward. Personally I think I can operate the Yanmar just as quick if not quicker then I did the hst and you have the added bonus of being able to control speed in the Yanmar with the pedal just like you would in a vehicle. When you add in the A/B function available on the Yanmar and you learn to use it properly it makes running the tractor a breeze. As for the clutch, I never use it in normal operations, the only time I do use it is when changing the speed selector from 1st, 2nd, or 3rd. It can be used to instantly stop power to the driveline if you needed to but in normal work you will use it very little if at all.

 

[ptsg]

From what I've seen about that transmission, it's like a small scale Vario transmission of a Fendt tractor. Albeit quite a bit complex, specially for a CUT, it's a great transmission. So, if you search for Fendt Vario Transmission, it may come up with some better info that may provide a better understanding of how it works.

It retains the mechanical drive train for efficiency and simply uses the HST to adjust the speed of the planetary drive. So the HST is basically doing light work and therefore it's not reducing the efficiency like the conventional HST tractor.

 

[presnewt]

I have a YT359C and before that I had a kubota with Hst. The Yanmar has a shuttle shift on the steering column for forward and reverse, power comes from a pedal just like the gas pedal in your automobile. You press the pedal to move forward and if you want reverse you simply ease off the pedal, switch to reverse and press the pedal again. With practice you can do this without fully letting off the pedal and it does work extremely fast. The major difference in the Yanmar verses a hst is that the Yanmar works very similar to the older tractors you are use to. On an hst, once you lift your foot from the pedal the tractor stops, on a Yanmar if you totally lift your foot from the pedal the tractor will continue to “creep” either forward or backward. Personally I think I can operate the Yanmar just as quick if not quicker then I did the hst and you have the added bonus of being able to control speed in the Yanmar with the pedal just like you would in a vehicle. When you add in the A/B function available on the Yanmar and you learn to use it properly it makes running the tractor a breeze. As for the clutch, I never use it in normal operations, the only time I do use it is when changing the speed selector from 1st, 2nd, or 3rd. It can be used to instantly stop power to the driveline if you needed to but in normal work you will use it very little if at all.

Thanks , that helps a lot. It seems more complicated and I worry about the reliability of it even though I have really heard nothing but good things about Yanmar. I wiil be mowing on some hills and my major reason for wanting HST is that it seems a little safer to me...take foot off pedal and unit stops. I don't want anything that I need to use clutch to brake or stop the tractor. I feel that in a stressful situation on a hill, I would rather avoid the clutch. It may not be a big deal for some folks but it is for me.

 

[wileythedog]

Thanks , that helps a lot. It seems more complicated and I worry about the reliability of it even though I have really heard nothing but good things about Yanmar. I wiil be mowing on some hills and my major reason for wanting HST is that it seems a little safer to me...take foot off pedal and unit stops. I don't want anything that I need to use clutch to brake or stop the tractor. I feel that in a stressful situation on a hill, I would rather avoid the clutch. It may not be a big deal for some folks but it is for me.

I have some pretty steep hills on our property....pretty much all 52 acres are hilly. My YT359C has no problem going up or down...but does feel tippy sometime going across. I have never come close to rolling, I just go slow...but my seat of the paints meter sinches up. I am pretty new to tractors still, and think it probably can handle much more than I give credit...but I'll stay on the safe side regardless. I reversed the front wheels, added 2.5 inch rear spacers and filled the tires (R1 tires). Still feels tippy sometimes, so will be moving to 5 inch spacers for the rears. Think that should do it for my purposes. Transmission is not the problem, it works fine!

 

[freightboy]

The transmission has been in use since 2006 worldwide and 2016 in the US. Look on any forum, they don't talk about failures. How it works in laymen terms. When in the working range the transmission couples together on the shaft and provides power like a gear driven tractor. The simplicity of operation of a hydrostatic transmission gives the best of both worlds. The power reverser (shuttle shift) controls direction, the accelerator pedal controls ground speed and the hand throttle controls the engine (PTO and Hydraulic) speed. The travel speed is not limited to where the hand throttle is set when using auto throttle (push the pedal, go faster). The I-HMT gives a few added features that may take a little to learn but once you learn them you will love them. Precise ground, engine and PTO speed can be set by using A/B mode.
There is a throttle boost that will raise the engine to maximum speed (as set in A/B mode) instantly by just pressing a button. This will not increase ground speed, that is controlled by the accelerator pedal. This is useful when lifting something heavy with the loader or other applications where you need instant power.
The A/B mode allows the operator to switch between settings (Engine/PTO, Ground speed) by simply pressing a button. A good example of why this could be needed is mowing with a rotary cutter. If mowing light brush, (my setting in A mode) I want 540 PTO RPMs and a travel speed near 5 MPH. When I get to a part of a field with thicker vegetation I can switch to B mode and keep 540 PTO RPM but slow my maximum ground speed to 2 MPH. Spreading fertilizer may be another use.
Once you get used to the noise and the slight creep, you will love it. It is powerful and easy to operate.

 

[Williy]

Have you seen these:

willy

 

[presnewt]

Have you seen these:

willy

I have seen that video and another one that did help. I have spoken to a dealer and am gonna get a quote from them at least to see how they stack up price wise.

 

[freightboy]

This has some good info also.