Kubota 3710 or 4310 GST or HST?

[MDSteve]

I was in the same boat about 4 months ago. I picked the 3710 with HST. I do not plow or plan on it but for mowing and using the FEL it works great. Many times when I was driving the tractor I have said to myself "HST was a good choice I am glad that I don't have to think about shifting and can concentrate on the task at hand." I have been very happy with mine. I also use a 72" rotory cutter and 72" rear finish mower.

Steve

 

[karmakanic]

I'm not an expert on this subject. But I think I can clear up some of the confusion. The basic difference between the GST and the HST is not whether they have gears or not, it's how they couple the engine to the transmission gear sets. Both of them use gear sets. The gear sets are coupled with either a conventional clutch/pressure plate combination in the case of GST or with a variable displacement hydraulic pump running a fixed displacement hydraulic motor in the case of the HST.

The GST is basically a conventional clutch/pressure plate coupling, but you do not have to depress the clutch petal to shift from forward to reverse, or to change gears. There are electrically operated servos that do the clutching for you. You have a lever that allows you to select forward or reverse, and you can move instantly from forward to reverse using this lever. There is another lever that selects the gear desired. Youn can shift on the fly from one speed range to another. You have a clutch petal that works like a regular clutch for idling in gear, or inching forward/back.

The hydrostat trans as used in the Kubotas consists of a variable displacement hydraulic pump plumbed to a fixed displacement hydraulic motor which is in turn coupled to a conventional 3 speed gear trans. You control the displacement of the hydraulic pump and the direction of hydraulic fluid flow with the foot petal. This gives you the ability to idle in gear without moving and instant reverse. But you cannot change from one speed range to another on the fly, you must stop the tractor to change speed ranges via the 3 speed gear trans. You also have up to 20% loss of hp thru the hydraulic pump/motor.

With a conventional gear trans. (not GST) you have to depress the clutch, stop the tractor, and then shift to the gear wanted. A shuttle shift trans adds a lever to the standard gear trans. that allows you to go directly from forward to reverse without using the normal gear shift lever. These were originally developed for loader work. I think some of the shuttle shift trans also have a servo to operate the clutch when using the shuttle shift, but I'm not sure.

HTH
Dave Perry aka karmakanic

 

[Miklos]

I would like to add one addition to help others avoid confusion.

On most shuttle shift tractors, where a foot operated clutch is used, the main transmission is fully synchronized and can be upshifted and down shifted on the move, without stopping, just as a stick shift automobile can be. You do have to fully stop to shift between hi-range and lo-range.

When pouring over tractor specs, notice the terminology used. "Collar shift" is NOT synchronized and then the tractor should be stopped for EVERY shift.

 

[woodyed]

Thank you very much and also thanks to Milkos for your replies. You have cleared up a lot of the confusion for me regarding some posts that I have read. I had planned anyway to ask the dealer to drive both GST and HST versions, and this should help me determine which version I want. I think I'm going to wait until the new improved versions of the Grand L series Kubotas hit my dealers in September, before I really pursue the driving trial though. From what I've been told they are changing the hood opening position, locating the 3 pt. hitch cylinder externally instead of internally, boosting the hydraulic flow and pump size for the power steering and implements, relocating the tie rods, improving the seat, and other cosmetic changes. These sound like some good improvements, especially the hydraulic changes, so I guess I will wait. Thanks again fellas for your transmission clarifications.