HST vs. Shuttle shift

[Tx Jim]

ovrszd
IMHO type of trans or type of trans control(shifter) has nothing to do with different ""types of shuttle shifts"". Would you give your theory of how type of trans or how trans is controlled changes type of shuttle shift?
Thank you,Jim

 

[ptsg]

Isn't that just nitpicking at this point?

Different types of shuttle transmission are built differently. It's not just the control of it that changes.

 

[ovrszd]

ovrszd
IMHO type of trans or type of trans control(shifter) has nothing to do with different ""types of shuttle shifts"". Would you give your theory of how type of trans or how trans is controlled changes type of shuttle shift?
Thank you,Jim

Oh my Jim.... Okay, I'll use your 7040 since you are familiar with it. For those that might not know, Jim has a Hydraulic Shuttle lever. A Transmission shifter lever giving him either 4 or 6 gears, they are synchronized. And last a Range lever giving him "high" or "Low". So he either has an 8 speed or a 12 speed. If he has his transmission in 3rd gear and range lever in low, he's in 3rd gear. If he wants to be in 6th gear he leaves his transmission shifter in 3rd and changes his range lever to high. This requires a complete stop. Can't change the range on the move. He's a couple steps better than the most mechanical type of shuttle shift. He's light years worse than the best shuttle shift.

An example of the better/best type of shuttle shift would be the JD road grader that I run. I described it earlier. Here's a condensed version. It's a hydraulic shuttle 8 speed. All power shift on the 8 speeds, no clutch, no stop. Can be running down the road at 28 mph in Forward 8th, toggle the shifter to Reverse and the grader will downshift until it stops forward movement, shift itself to Reverse and start moving in 4th, then upshift thru the gears until it's in Reverse 8th, again going 28 mph. No clutch, no braking, full throttle.

So Jim, would you say these two example of shuttle shift are the same type?

 

[ovrszd]

Isn't that just nitpicking at this point?

Different types of shuttle transmission are built differently. It's not just the control of it that changes.

Absolutely nitpicking. Jim has done this with me on different subjects before. Very predictable.

 

[Tx Jim]

Isn't that just nitpicking at this point?

Different types of shuttle transmission are built differently. It's not just the control of it that changes.

I never stated or implied control of shuttle shift wasn't involved in type of shuttle in fact IIRC I stated it was involved. You can call me nitpicking I call it clarification.

 

[k0ua]

And there are several types of Hydrostatic transmissions. The basics are just a variable displacement piston pump with a swash plate who's output fluid drives a fixed displacement hydraulic motor that drives an old non synchronized 2 or 3 speed gear transmission (the so called range shifter). BUT there are variations on that theme like the Kubota Hydrostat + which has a two speed motor so it "doubles" the ranges, and also electronic controls to control throttle and swash plate angle. Also some of the swash plates are directly controlled by the operators foot, and some are hydraulically controlled and some are electrically/hydraulically controlled. Cruise controls can be mechanical, or electric/magnetic or maybe by electronic means.

But I really don't want to get into this discussion.

 

[ovrszd]

And there are several types of Hydrostatic transmissions. The basics are just a variable displacement piston pump with a swash plate who's output fluid drives a fixed displacement hydraulic motor that drives an old non synchronized 2 or 3 speed gear transmission (the so called range shifter). BUT there are variations on that theme like the Kubota Hydrostat + which has a two speed motor so it "doubles" the ranges, and also electronic controls to control throttle and swash plate angle. Also some of the swash plates are directly controlled by the operators foot, and some are hydraulically controlled and some are electrically/hydraulically controlled. Cruise controls can be mechanical, or electric/magnetic or maybe by electronic means.

But I really don't want to get into this discussion.

Excellent explanation James!!! You've thrown yourself under the bus!!!

 

[k0ua]

Oh, and to the Original Poster, aren't you really really glad you asked about the difference between shuttle and hydrostatic transmissions?

You never knew it was all this complicated and would bring so many people out of the woodwork did you?

 

[Tx Jim]

ovrszd
After being employed at a JD dealership for 21 yrs with 13 of those yrs serving as dealer service manager I'm probably as much or more knowledgeable about a JD Powershift trans as you. But in my opinion Powershift trans is just that a semi automatic trans not a TRUE shuttle shift which this thread was originated about but if you want to call it a shuttle shift is fine with me.

 

[ovrszd]

ovrszd
After being employed at a JD dealership for 21 yrs with 13 of those yrs serving as dealer service manager I'm probably as much or more knowledgeable about a JD Powershift trans as you. But in my opinion Powershift trans is just that a semi automatic trans not a TRUE shuttle shift which this thread was originated about but if you want to call it a shuttle shift is fine with me.

With that criteria, all of James' examples are just one type of HST.

 

[scratchpad]

Oh, and to the Original Poster, aren't you really really glad you asked about the difference between shuttle and hydrostatic transmissions?

You never knew it was all this complicated and would bring so many people out of the woodwork did you?

Great information but a little complicated to understand and confusing to me at this stage of the game. I am glad i asked. For me, it would be best to go out and drive all different types and see what fits me and my situation best.

 

[ovrszd]

Great information but a little complicated to understand and confusing to me at this stage of the game. I am glad i asked. For me, it would be best to go out and drive all different types and see what fits me and my situation best.

Most definitely.

I have 1 HST, 1 Mechanical Shuttle, 1 Power Shuttle and 1 Torque Converter Power Shuttle. Each one perfectly matches the size and expected work of the tractor.

Contrary to much debate, there's no one perfect drive system.

 

[k0ua]

Great information but a little complicated to understand and confusing to me at this stage of the game. I am glad i asked. For me, it would be best to go out and drive all different types and see what fits me and my situation best.

The long and the short of it is the hydrostat will give very precise control, infinitely variable ground speed that you can vary near instantly, and will allow you to creep slower than the slowest creep gear transmission ever made. This is useful when doing work with forks around delicate and expensive equipment. The shuttle has the advantage of better fuel economy, no loss of power (to speak of) like the hydro has, No hydro whine no excess heat to dump. Hydro machines are even easier to operate than the shuttle's. but the shuttles are not hard to operate either. Hydro's are often seen on smaller tractors, but they have been more popular in larger units of late. MOST homeowner tractors are hydro. Larger "farm tractors" are rarely hydro. To most homeowners the convenience of operation and some of the positives the hydro brings to operation outweighs the loss of power in the form of heat. In many way the hydro transmission is simpler from a mechanical standpoint than the shuttles. The hydro is NOTHING like an automatic transmission in a car or truck.

 

[k0ua]

Contrary to much debate, there's no one perfect drive system.

Truer words have never been spoken. :thumbsup:

 

[k0ua]

Great information but a little complicated to understand and confusing to me at this stage of the game. I am glad i asked. For me, it would be best to go out and drive all different types and see what fits me and my situation best.

I have a favorite saying, that others may not agree with, but it goes like this: "If you don't know what kind of transmission you need, then you need a hydrostat".

It seems to fit most of the time. Good luck in your quest.

 

[kenmac]

Heck , Just buy both. I have a 50 hp HST and a 105 HP shuttle

 

[5030]

May I ask your definition of the word "MANY"?? Sounds to me that most type shuttle shifts have been covered in this thread. My Kubota M7040 hyd shuttle control has no electrical connections except for neutral start switch because it's cable controlled. I think clutch pedal is mechanically connected to hyd valve but Ill have to check tech manual to be sure. I also have no knowledge of Glide-shift.

You are correct. No mechanical linkage. F&R is via a wet pack, hydraulic actuation via a valve on the side of the main case and lockup pressure is adjustable (just adjusted mine). No clutch in the bellhousing, just a flex plate and damper springs. Transmission is 'clutched' via the wet pack. the clutch pedal acts on the valve just like the F-R shuttle lever acts on the pack. Both my M9's are 'hydraulic shuttle'

I prefer that over an HST because with an HST you have parasitic loss from the fluid coupling plus it generates heat just like an automatic trans.

A hydraulic shuttle is a gear transmission (no parasitic loss) coupled to a multi plate wet clutch and no dry clutch to ever wear out. I have 4000 hours on one of my M's and the system has never been touched.

 

[Texasmark]

mikester's reply was not exactly perfect. There are 2 types of shuttle shifts. Hyd type which he mentioned but there's also a synchronized type that one must depress traction clutch control pedal to shift from fwd to rev or vice-verse. I once owned a Kubota M4900 with sync-shuttle that required having the reverser replaced due to synchronizer failure & it locked in reverse.

My 6530 uses a clutch but you don't even think about it. You move the shift lever while your leg is moving and you're done.

 

[Texasmark]

I'm glad my dog decided to stay on the porch, next to my rocking chair, getting his head rubbed.

 

[mpsmith60]

HST uses oil to drive the wheels. Think of an automatic transmission in a car. Usually one pedal to go forward, one for reverse. The harder you push it, the faster it goes.

Shuttle shift is a manual transmission with an added feature - an automatic clutch mechanism so you dont have to put the clutch in when changing directions. You control your speed with either a foot or hand throttle and gear selected.

It comes down to personal preference. Ive had both and now prefer the HST on my M59 because I get better fine tuning with infinitely variable speed control. Perfect for loader and finishing work. What I miss on the M59 is cruise control, so bush hogging was easier for straight aways on the shuttle shift, but HST is better when I need to change ground speed around obstacles without losing PTO RPM. I can do all my mowing in high gear and just adjust my ground speed with a touch of the pedal.

Smaller HST machines might have less power going to drive the wheels than SS, but On the M59 power delivery has never been an issue.

I chose HST on my L3901 and have never regretted it. I do a lot of loader work and the ease of HST is great. Plus, like you said, I like that I can speed up or slow down without changing PTO speed.