Why use clutch with GST?

[Ben3130]

I have a 3130 GST, and in my limited use of my PTO (just post hole digging so far) the clutch has no effect on PTO operation. My PTO is controlled by the PTO lever on the right fender. My owners manual only makes reference to this lever when discussing PTO operation. I have not done any extensive testing to see how 'independant' my PTO really is, I won't get to do any tractoring until this weekend.

 

[KennyV]

I think GregH has a good point about shifting to reverse while mowing at pto speed.
However using the GST to drop to lower gears before making a change in direction, will keep clutch friction heat to a minimum, the heat is dissipated into the hydraulic oil covered clutch pack instead of the dry clutch pressure plate and disc.
You could also throttle down before reversing (engine has plenty torque to bring pto back to speed). I normally slide to a lower gear, letting the hydraulics do the clutching and gear changes.

Also as mentioned by JKUB I also think all Grand L’s with GST have independent pto.KennyV

 

[Jay4200]

Just my opinion.... NEVER engage or disengage an implement of any significant rotating mass without using the clutch. Even at idle, engaging a bushhog is a lot of stress to to instantly put on the PTO. Using the clutch will buffer that stress.

My GST's clutch will disagage the PTO. The shuttle shift or shiffting through the gears will not.

If, however, the PTO has it's own hydrostatic clutch, which is what Kenny is saying, then it won't be a sudden whack when it's engaged. I do think you are right about the clutch disengaging the PTO - at least that's the way I remember it. It probably also has a hydrostatic clutch too. GSTs are best-of-all worlds, after all .

Not that I'll ever find out - I bought my L4200 specifically to use as a backhoe (that I could actually tow with a pickup) - and removing my Woods backhoe looks like enough work that I'll probably never do it. The only reason I spun the PTO was so I could say, "Yup, the PTO works" in case I ever wanted to sell the tractor.

Jay

 

[GaryE]

OK it’s coffee (and donut) time…

OK, I just went out, started up my L3710 GST engaged the PTO, pressed in the clutch and guess what??? The PTO STOPPED spinning! It would seem Kubota is not consistent on how it handles this. Mine is the older style (non electronic) system. But I do not think that is the difference, GregH says the clutch on his L4310 GST (which I think is the same transmission as mine) does not effect his PTO.


Now the real problem... Who is buying coffee and donuts?


Gary

 

[Jay4200]

OK, I just went out, started up my L3710 GST engaged the PTO, pressed in the clutch and guess what??? The PTO STOPPED spinning! It would seem Kubota is not consistent on how it handles this. Mine is the older style (non electronic) system. But I do not think that is the difference, GregH says the clutch on his L4310 GST (which I think is the same transmission as mine) does not effect his PTO.

Oh great, now I HAVE to go out and try it myself.

Jay

 

[KennyV]

GaryE…
I think I have found the answer… but not to the coffee question.
I got to digging around in my Kubota books and found a 2001 Kubota booklet on the Grand L series that covers L3010/L3410/L3710/L4310/L4610… and on the fourth page just past half way down, It mentions that the “Live-Independent PTO” is only available on specific models… evidently the L3710, although in the grand L series, and a GST, dose not have Live Independent PTO…. See the attached scan of that part of this booklet. KennyV.

 

[GaryE]

GaryE…
I think I have found the answer… but not to the coffee question.

KennyV,


Good find! That would explain the difference. Never even crossed my mind this might have been an option!


Now the real problem, who buys?



Gary

 

[johnk]

KennyV,

Mine is a Grand L3130 and it has an independent PTO. The foot clutch has nothing to do with the PTO on mine so it's not just a 3710 or specific model. I think all the Grand L's have them. At least the newer ones in the last few years...A little Note in the manual.*****

Tractor will not start if PTO lever is in the "ON" position.***When the clutch pedal is depressed the PTO disengages { on the HST MODEL]

When the clutch pedal is depressed on a [GST, DT, Model] the PTO engages.......Hope this helps a little further.........

 

[jmcalli]

There are differences among the models in the Grand L series. I got this information from the Kubota Grand L Series sales brochure Specifications page. The L4200GST was only available with independent PTO but the other Glide Shift Transmission-equipped (GST) models in the Grand L series (L2900GST, L3300GST, and L3600GST) may have been equipped with either live (non-independent) or independent PTO's. The L3600GSTC (cab model) and the L4200GST, were only available with independent PTO but all the other models could have either type.

Regarding operation of the independent PTO, the Kubota Operator's Manual states:

______________________________________________________________
PTO Clutch Control Lever [With Independent PTO type]
(1) The tractor has a 540 rpm speed position.
(2) The PTO clutch control lever engages or disengages the PTO clutch which gives the PTO independent control.

Shift the lever to "ON" to engage the PTO clutch. Shift the lever to "OFF" to disengage the PTO clutch.

IMPORTANT:
-To avoid shock loads to the PTO, reduce engine speed when engaging the PTO, then open the throttle to the recommended speed.
-To avoid damage of PTO clutch and implement, shift the PTO clutch control lever slowly, when engaging the PTO clutch. Do not keep the PTO clutch control lever half way.

NOTE:
-There is a PTO-1 (540rpm) indicated mark on the tachometer board.
-Tractor engine will not start if PTO clutch control lever is engaged "ON" position.
_______________________________________________________________


It should be noted that the instructions for the live (non-independent) PTO state, "PTO shifting needs clutch operation. Press the clutch pedal down completely to stop the tractor movement and any PTO driven equipment movement before shifting the PTO gear shift lever." Also, "To avoid damage of transmission, before shifting the PTO gear shift lever, fully disengage the main clutch."

So, according the the Operator's Manual, the L4200GST does not require clutch operation to engage the independent PTO, but it does recommend backing off the throttle before engaging it.

Just having a GST model Kubota doesn't guarantee that you have an independent PTO. If you have a live PTO you will need to use the main clutch. You need to check the operation of the PTO clutch control lever (with the foot clutch disengaged) to verify the type of PTO you have.

 

[Jay4200]

The L4200GST was only available with independent PTO

Shift the lever to "ON" to engage the PTO clutch. Shift the lever to "OFF" to disengage the PTO clutch.

So, according the the Operator's Manual, the L4200GST does not require clutch operation to engage the independent PTO, but it does recommend backing off the throttle before engaging it.
QUOTE]

Thanks for the clarification. I knew that the tractor wouldn't start with the PTO lever in the on position - which, incidentally took me FOREVER to figure out the first time (kids evidently threw the lever while playing on the tractor) - it all makes sense now.

Jay