About to buy: GST vs. HST

[PoorPlowboy]

I don't understand. HST uses oil to transmit power as does an automatic tranny in a car....right? With HST there is also infinite amount of possible speeds, which and Auto tranny in a car does. How would a gear drive with hydraulic shifting be more comprable?

No. The only thing the hydraulics do in an automotive style automatic is move the input gear within the transmission to a different output gear. It simply removed the requirement of the driver to manually shift. The gears are still there. Not so on a HST tractor.

The only automotive automatic that will honestly give you infinitely variable speed like you're attributing to an HST tractor is the CVT continuously variable belt driven transmission found on some Nissans and Hondas. A regular automotive automatic tends to burn the clutches and hyd fluid when they're treated as an infinitely variable trans.

 

[crazyal]

GST seams more like a standard transmission to me. In an automatic you have a torque converter and the gears are automatically selected.

 

[kubotadriver4life]

GST seams more like a standard transmission to me. In an automatic you have a torque converter and the gears are automatically selected.

I agree. There is no shifting, nor clutch and gear selection is optional. The Glide Shift just basically means you can shift without stopping the tractor, the same thing you can do with a stick in a car.

 

[bigbull338]

if thats the case then the GST is just like the selecto speed tranny.the selecto speeds could be shifted on the go after they was put in gear.

 

[kuboman]

I don't understand. HST uses oil to transmit power as does an automatic tranny in a car....right? With HST there is also infinite amount of possible speeds, which and Auto tranny in a car does. How would a gear drive with hydraulic shifting be more comprable?

I want to make sure i have this right.

GST:
hydraulically shifted gear transmission. It is able to shift up or down on the fly without using the clutch. They just use a hydraulic actuator to eliminate the need to stop the tractor and clutch into a different gear. Correct?

HST:
A hydraulic pump that the displacement can be varied, that then drives a fixed-displacement hydraulic motor. Correct?

An automatic is basically a power shift transmission with clutches and planetary gear sets driven by a fluid coupler. A hydrostatic is a variable displacement pump driving a hydraulic motor. The only similarities are they both use oil.

 

[RobertN]

My two tractors have been HST, previous Kubota, and current NH> Both have worked well. I have rented Kubota L35TLB GST's; I liked that tranny once I got used to it. The GST was definitely quieter; both my Kubota and NH definitely have hydro-whine...

 

[PapaPerk]

I don't understand. HST uses oil to transmit power as does an automatic tranny in a car....right? With HST there is also infinite amount of possible speeds, which and Auto tranny in a car does. How would a gear drive with hydraulic shifting be more comprable?

I want to make sure i have this right.

GST:
hydraulically shifted gear transmission. It is able to shift up or down on the fly without using the clutch. They just use a hydraulic actuator to eliminate the need to stop the tractor and clutch into a different gear. Correct?

HST:
A hydraulic pump that the displacement can be varied, that then drives a fixed-displacement hydraulic motor. Correct?

No a hydrostatic transmission on a tractor is nothing like an automotive automatic transmission.

The typical automatic transmission uses a series of planetary gear packs that are stopped and released by clutches. By changing which part of the planetary rotates, the gear ratio is changed. An automotive automatic trans is a GEAR driven transmission.

A hydro transmission uses a pump to force high pressure fluid through a hydraulic motor. The motor is linked to a 2 or 3 speed gear box that allows the operator to choose which "range" they want to operate in. A hydro transmission is a Fluid driven transmission.

A GST transmission uses an actuator and wet clutches to shift the trans for you. This is most similar to an Automotive transmission and nearly identical to high performance autos used in Ferrari, Audi, etc.

 

[PapaPerk]

I agree. There is no shifting, nor clutch and gear selection is optional. The Glide Shift just basically means you can shift without stopping the tractor, the same thing you can do with a stick in a car.

That is inaccurate. You do not have to clutch a GST transmission. It has an automatic clutch. It is nothing like a manual transmission in a car.

 

[aczlan]

Go with the HST.
Dad has a L3650GST and my father in law has a B7500HST. The HST is much easier to do loader work with and we have not had any HST related issues when tilling. Yes, the tiller will "push" the tractor a little, but it is about like going downhill.

Loader work is easier with HST as you use your feet to control fwd/rev directions and your hands to run the loader or steer.

Aaron Z

 

[bilrus61]

I bushhogged today on my L5040 glide shift with a 6 foot bushhog. I mowed a little over a hour and was thinking of how it would mow with a HST vs. a GST. I decided that the GST is , to me, better at bushhogging and here is why I think so.

My field was very variable. Steep hillsides and a low drainage between them. It had not been mown in quite some time. Some trees were about 4 feet tall and in the flat the weeds/briars were HUGE. Way over my head, 8 feet tall and very thick. But as I mowed up the hill to the top the growth became much thinner. Just about 2 feet tall dryish grass that was very easy to mow in 5th gear. I was able to make my speed adjustment per the wildly different growth by just a quick touch on the gear shift lever. On the hillside I would bump it up to mow in 5th gear. Then when I headed down to the bottom of the "valley" I would just pull back into 4th and one time had to go all the way down into 2nd for a few feet. I was able to think about my steering and the turns without thinking of keeping the correct pressure on the speed pedal or having to set the cruise control over and over. Hit some rough ground (groundhog holes) a few times and bounced in my seat pretty good. Tractor just kept on chugging in 4th. If I was using my mom's B3030 I couldn't have maintained that speed and efficiency. I was able to relax and change speed to the match the load with just a minor movement of my left hand. Once in the right gear I didn't have to think about or try to keep the proper speed. It did it by itself.

Imagine a car driving down the interstate with cruise control (GST) on or having to try to keep a constant speed with the gas pedel(HST). So much more relaxing and easier to chug down the road with cruise on. While I'll say that a HST would be better for lots of back and forth loader work, I think that tilling work would be a wash and for bushhogging the GST would be slightly the best.