What is correct way to drive an M7040 with hydraulic shuttle shift?

[Fallon]

I'm surprised how this thread has gone on to 40 posts. And had me puzzled more than once about which transmission was under discussion. I found a site at What is this Shift? Understanding Kubota Transmissions — Humphreys' Outdoor Power which describes in very good detail the plain gear drive, HSD, GST and HST types of Kubota transmissions. The GST (being a stick shift with no requirement to use the clutch) seems to be unique to Kubota. Interesting.

John Deere has PowerShift, which functions like GST. I believe it's a dual clutch constant mesh system. At any rate shifting is in the millisecond range not the 1-2 second range. PowerShift is on bigger JDs. Not sure if Kubota has a competitor in that range of machine. Also not sure if JD or others have anything like PowerShift or GST on smaller machined.

Any mid or high end sports car has similar technology these days. Porsche, Ferrari, Lamborghini & most other high end machines don't even offer a transmission other than a flappy paddle gearbox (more or less GST or PowerShift). Wouldn't surprise me if more than just JD or Kubota had it in the tractor world.

 

[sixdogs]

Not sure I even had an option on my M when purchased in 2012. Hydraulic Shuttle. Only choice was 8spd or 12spd or 24spd (with creep).

What trans do you have?

 

[ovrszd]

What trans do you have?

Hydraulic Shuttle 12 spd. 6 gears doubled by 2 ranges. 6 speed is synchronized. Must stop to change ranges. Great gear selection for field work.

 

[David_Kb7uns]

John Deere has PowerShift, which functions like GST. I believe it's a dual clutch constant mesh system. At any rate shifting is in the millisecond range not the 1-2 second range. PowerShift is on bigger JDs. Not sure if Kubota has a competitor in that range of machine. Also not sure if JD or others have anything like PowerShift or GST on smaller machined.

Any mid or high end sports car has similar technology these days. Porsche, Ferrari, Lamborghini & most other high end machines don't even offer a transmission other than a flappy paddle gearbox (more or less GST or PowerShift). Wouldn't surprise me if more than just JD or Kubota had it in the tractor world.

The JD Powershift is 2 transmissions side by side the GST is 1 transmission.

David

 

[Tx Jim]

The JD Powershift is 2 transmissions side by side the GST is 1 transmission.

David

David
Would you please explain how you think a JD powershift is 2(two) transmissions? Granted a powershift trans has planetairies & clutch packs but each rely on each other for different speeds(gear ratio's). Thanks,Jim

 

[Fallon]

David
Would you please explain how you think a JD powershift is 2(two) transmissions? Granted a powershift trans has planetairies & clutch packs but each rely on each other for different speeds(gear ratio's). Thanks,Jim

It's not entirely inappropriate. I believe they are constant mesh transmissions. When you are in 1st gear, it already has shifted into 2nd on the alternate pathway. It just let's out the first clutch while letting in on the 2nd. It's unbelievably fast when shifting. However you can confuse it. If you say shift from 1 to 3 & it expected you to shift to 2nd there is a lag as it has to shift & clutch on demand rather than just clutch on demand.

I remember running into that lag back in the day & have seen similar notes on JD's site recently.

 

[David_Kb7uns]

Well not quite 2 totally but, there are 2 clutches and 2 main shafts and the clutches are alternated between odd and even geers as the shifts are made. Most diagrams I have looked at have odd gears on one shaft and even gears on the other.

The Kubota GST is just a gear transmission with hydraulic pistons moving the shifting forks and is not constant mesh or planetary gear sets with bands.

David

 

[mike69440]

I never shuttle under throttle, always at engine idle speed.

You can shift trans speeds without the foot clutch, on the go, simply by bumping the shuttle to neutral. Friend of mine has an M8540 and has left leg limitations and does it all the time.

I believe my M9540 system to be much more durable and strong than my operations require. I use my tractor hard. I try to never abuse it.

About the nastiest thing I do with my L39 GST is plow snow. Generally RPM is 2200-2500 RPM and I do shift under power. I try to de-clutch and ram a snow bank, brake, or coast to stop when F/R. I Try to Plow at 5 MPH of faster. +2000 hrs on 2005 year tractor.
I hate snow plowing. Tough on tractor, especially on gravel.

 

[arobint]

Glide Shift is not constant mesh like PowerShift is and has only fork shifted synchronized gear sets with ECU modulated hydraulic multi disk clutches.

David

Which one does a 2013 M7040 with hydraulic reverser have?

 

[ovrszd]

Which one does a 2013 M7040 with hydraulic reverser have?

The 7040 has a synchronized 4 or 6 spd transmission with a non synchronized 2 spd range. Foot operated hydraulic clutch as well as a hydraulic shuttle lever. The shuttle lever is 3 position F, N, R. Shuttles without use of foot clutch pedal and functions like an auto trans in regards to starting movement. Is the only means of changing direction.