L2950 GST question

[manugoss]

Hi

I bought a lightly used Kubota L2950 GST few weeks ago. It will be used for snow removal during wnter but mainly with a log loader in the woods. I used to have a Kubota sunshine Li-24 but someone stole it. I have to say that I love the GST transmission. It works great for snow removal in a driveway. You can easily adjust speed for the snowblower demands. The only thing I don't like about that transmission is the delay to engage movement when the lever is engaged. On my tractor there is several second beteween the time you ''shift'' and the time the wet clutch engage. Lets say the tractor is under load then when I shift from 6 to 7th gear lets say, the tractor will loose speed du to that clutch delay and then it catches in an unsmooth manner. If the dealy was shorter than it would catch more evenly. Is there a way to shift smoothly or is the clutch not ajusted properly? I am concerned about the clutch not catching smoothly because I want to make sure it last a long time. Thanks for your inputs.

 

[KennyV]

I use my right foot on the throttle feed and lightly reduce the engine RPM when up shifting and slightly increase the engine RPM for a down shift. Try that several times and you will get the hang of the proper lag and you will have silky smooth shifts. This change in RPM is not enough to rob your pto speed you will like the results.
The wet clutch packs are very durable and dependable, but a smooth shift is still much nicer on everything than a sharp jolt. KennyV.

 

[manugoss]

Is there a way to ajust that lag? I wish the delay was shorter. I will try your recommandations the next time I run the tractor. I hope that will do it. Thank for the input.

 

[KennyV]

"Is there a way to adjust the lag?"
Well yes and no...
It is greater with heavier hyd/tran fluid, and lesser with lighter viscosity fluid. SUDT is Kubota's multi-viscosity fluid, that may help a little bit, BUT they price that stuff as if it was a synthetic (it is not a synthetic).
The best solution is to use a true synthetic because it flows MUCH better in the cold (snow moving months). The problem is that it's gallons of $$$.
The lag should be a lot less as everything heats up using UDT. I have been using Travelers premium hyd/trans from Tractor supply for many years, just allow everything to heat up in the winter.
Allowing a little engine rpm increase on a downshift and a little decrease on up shifts have always worked great with my GST, but in Kansas it's never really that cold in the winter. Where are you located?

 

[Baby Grand]

KennyV described the shifting technique that I use with my GST. It's very similar to clutchless shifting a manual transmission in a car or truck. I used to do this on a regular basis with a Mack Quadruplex R600 (5x4 speed) that I drove for a lumber company. That truck's transmission was designed for that style of shifting. With a modern car it's not such a good idea, but it can be done.

The benefit when you do it on a GST tranny is that you are matching the speed of the two rotating shafts prior to engaging the wet clutch, which makes shifting the GST much faster and way smoooooother, especially when you downshift. Besides, it's fun!

Try it:

How to Clutchless Shift | eHow.com

-Jim

 

[manugoss]

I am located in Quebec Canada. It makes sense that is temperature related because the only time I used it it was around -10 C and I only used it for 15 minutes on light work so probably the oil did not heat up that much. The next time I change the oil I will pay attention on the hydraulic oil viscosity at low temperature. I don't mind the lag it is just that I want to keep my tractor for a long time and I don't want to break anything. Thanks

 

[Yankee Clipper]

Manugoss,

The reason for the delay is on some shifts (4/5 especially) you are filling two servos as well as the GST clutch and moving the fluid takes time. They use a rotary valve - which can leak a bit when moving and while there is a low pass valve (which is supposed to keep everything full) but it can't stay with it on the 50 / 00 and 10 series GSTs, especially on cold units at the 4/5 shift. The Grand L30 and GL40 GSTs are electrohydraulic and have a temperature sensor that tells the controller the fluid is thick so it fires the required coils based on that input. The GL30/40 GSTs also have 12 forward and 8 reverse instead of the old 8 and 8 on the early GSTs. Big improvement and bullet proof on the electrical stuff as well.

Don't try to adjust the delay out on the older units - just know it is a characteristic of the early design.

Good luck!

 

[benelli]

I use this method as well on my GST. It does help.

 

[David_Kb7uns]

When I got the GL3130-GST it was a little sluggish on the shifts until the first service when I put SUDT in and it really changed for the better. Thinking now the dealer probably put UDT in it at first to be cheap but it does need the SUDT. I think from reading the schematics on the L3130 that the transmission electronic control unit has both travel speed and tachometer inputs so it will calculate the timing based on those inputs, not sure how the old ones do it. But when I run my unit I use the foot throttle and shift it like a stick and it is quicker and smoother.


David Kb7uns