GST Vs Gear drive

[GreensvilleJay]

curious am I

re: ' I believe the GST is fundamentally a gear drive with an electronic change/shifter ''

so is there a clutch ? if so do YOU have to depress it for every shift or does the 'computer' do that for you ? If so, the the GST is really a semiautomatic transmission ??

 

[PoTreeBoy]

curious am I

re: ' I believe the GST is fundamentally a gear drive with an electronic change/shifter ''

so is there a clutch ? if so do YOU have to depress it for every shift or does the 'computer' do that for you ? If so, the the GST is really a semiautomatic transmission ??

I'm only familiar with the L35s GST. The foot clutch pedal is connected to a conventional dry clutch. It's only required for intentionally slipping for fine control, and for engaging the PTO. The wet clutch is completely '(hydraulic) computer' controlled along with the gear and range shift. When you shift 'speeds', you're really shifting a hydraulic selector valve. The shuttle lever is physically connected to the tranny, but there is an internal hydraulic valve that disengages the wet clutch during the shift.
One characteristic of the GST I didn't mention before: since the clutch requires hydraulic pressure to engage, if you lose pressure for any reason you're in neutral. I experienced this a couple of times when going down a fairly steep incline and the (slightly low) fluid ran to the front, partially unporting the pump suction and leaving me with just enough clutch pressure to back up in 1st gear. If you're used to parking a gear tractor in low gear to keep it from rolling off, you're going to be in 'neutral' when you shut the GST engine off. The only 'park' you have is the foot brake and lowering the attachments. Maintaining the brakes is important on these tractors; the old farmers that ran around on their gear tractors with barely functional brakes would be in trouble.
As a mechanical engineer, I recognize what a design marvel this is to make work smoothly without electronics. Fortunately, it is reported to be generally reliable as long as clean, genuine Kubota fluid is used.

 

[GreensvilleJay]

thanks for the edumacation !!
I'm thinking HST would be better than GST. I always seem to need a'2.5' gear on my 8 speed big tractor...

 

[NCL4701]

For anyone still wondering how HST really works, this is a pretty good visual of the workings hydraulic motor that powers the gearbox. If your inputting pressurized hydraulic fluid into the unit it turns the shaft: thus it’s a motor. If you power the shaft and don’t pressurize the fluid, it’s a pump.

 

[vanhanz]

My experience, my previous tractor was an L3130 GST. I had no experience driving tractors so I had nothing to compare it to. It was actually about 4 months into ownership that I realized I could vary my speed with the foot throttle, until that point I only used the hand control throttle and gear selector . I ended up trading it in due to an expensive repair about a year later. I bought a brand new L3301 HST. Loader work was night and day easier with the HST. Using the foot pedal is much better than the hand lever Forward/Reverse for loader work. I do miss the extra power of the L3130 (It was less hp but it was a much bigger tractor, Grand L line, lift capacity was a lot higher) but I'm making due. If I had to do it all over again I'd find a deal on a used skid steer and get a older non-loader pulling tractor.

 

[North Idaho Wolfman]

I've read a bunch of post on here, but not all, so if I hit on points already pointed out sorry.

Yes a GST is a Gear drive tractor with a hydraulic shuttle clutch.
I like it because I can go from any gear to any gear at anytime.
It's a lot quieter to operate that a HST, no hydraulic wine.
You don't have to use the mechanical clutch to do anything, but fine control is easier with the clutch.
GST's baffle most mechanics, so be wary of that, I've fixed a lot of them because not many know how.
Fluid type and condition is very important with a GST as they do not like thick fluid or contaminated fluid.
They are a good general use tractor as they can pull implements like a DT yet give you some of the advantages of the HST ease of use.

 

[Old_Paint]

I'm gonna agree with everyone saying to evaluate the application. If you're getting it for farming or higher volume timber work where you go in straight lines or on roads for extended periods, yes a Gear drive or Shuttle drive is going to work best and create a lot less heat and be a lot more efficient for fuel use. If you're going to be doing landscaping, dirt work or anything similar that requires low speed/high torque and constant direction changes, rocking a pedal back and forth is a LOT better than constantly reaching for a lever. I got mine for the latter purpose, and having grown up around 8N's, Farmall's and MF-135's, hands down, working in the woods is a lot better with HST.

Just give some thought about what you're going to be doing most with it. If you will only be maneuvering in tight quarters, there's no substitute for HST. Open fields are a waste of fuel with HST, but the HST can save a ton of fuel and time by eliminating all the shifting of a manual when constantly changing directions. If it's maneuvering a backhoe application, shuttle shift might be better if you're digging long trenches, but HST might be perfectly suitable for more accurate positioning of the machine. Hands down, a manual is far better for tilllage or haying where constant speeds in one direction are needed for long periods of time.