Why use clutch with GST?

[KennyV]

Jay & Gary…
On your GST the foot clutch will not have any thing to do with the PTO…

‘Independent’ PTO… as on a GST the PTO has a hydraulic multi disc clutch pack that is independent of the of the drive system… hence the name ‘independent’.

On a transmission type PTO it takes the normal path using the foot clutch.
IF your foot clutch has anything to do with the PTO… then you do not have an independent PTO… KennyV.

 

[KennyV]

There was a past thread about feathering the PTO lever into engagement to prevent the ‘shock’ of PTO drive on heavy cutters and chipper, shredders. With most GST and hydro transmissions the PTO is independent and you can ‘feather’ the engagement of the hydraulic clutch pack. The old thread was outlining the concern of using electro hydraulic engagement switch on some of the most recent model tractors with independent PTO… With that set up there is NO WAY to slip the clutch pack into engagement. KennyV.

 

[john_bud]

Jay & Gary…
On your GST the foot clutch will not have any thing to do with the PTO…

‘Independent’ PTO… as on a GST the PTO has a hydraulic multi disc clutch pack that is independent of the of the drive system… hence the name ‘independent’.

On a transmission type PTO it takes the normal path using the foot clutch.
IF your foot clutch has anything to do with the PTO… then you do not have an independent PTO… KennyV.

Kenny,

Just for giggles, would you put the clutch down all the way, then engage the PTO switch. Keep the clutch down. I bet the PTO is NOT spinning. Let up the clutch and it will spin. While Kubota has an Indepenant PTO, it is not unaffected by cutting power from the engine to the transmission.

At least that's what I "think" will happen. If you can, would you please try it and let us know for sure?

Thanks!
jb

 

[KennyV]

John bud…
Hello John… As I said I have not used my clutch in years. I guess if you won’t take my word that my memory is working… I will take you up on your ‘bet’… If I know my tractor and the clutch has nothing to do with the PTO, You will owe me a cup coffee. If I’m wrong, I’ll buy you coffee for a year (of course if I’m wrong it will be because my memory will have failed and I might also forget to get you a years supply of coffee.). You will have to take my word for it when I check this for giggles, later this afternoon…

OR actually you won’t have to trust that I am basically honest… Jay can verify this with his L4200… Jay you can check this without hooking anything to your PTO. When the pto clutch pack is disengaged there is a disc brake that automatically is engaged. This will prevent it from turning when not turned on.
You don’t even need a second person to check if the pto is turning… Use the clutch lock down lever (under the clutch pedal), That will hold the foot clutch fully depressed. Turn on the PTO and step to the rear, you should see the PTO spinning… Turn the pto selector off, the pto should stop. When you are finished don’t forget to release the clutch lock down… Post what you find and I will actually check mine, and I will post back. Someone should have coffee… KennyV.
PS.. this should be fun. Also I am curious if all Kubota GST’s have independent PTO… so if you other readers of this will verify if your GST is or is not independent… Please post your results using this same test.

 

[GaryE]

John bud…
Hello John… As I said I have not used my clutch in years. I guess if you won’t take my word that my memory is working… I will take you up on your ‘bet’… If I know my tractor and the clutch has nothing to do with the PTO, You will owe me a cup coffee. If I’m wrong, I’ll buy you coffee for a year (of course if I’m wrong it will be because my memory will have failed and I might also forget to get you a years supply of coffee.). You will have to take my word for it when I check this for giggles, later this afternoon…

KennyV,


Honest!!! I do it all the time. The foot clutch WILL disengage the PTO. It WILL also disengage the drive train. But the shuttle shift and or the GST gear selector will ONLY disengage the drive train, that is how / why Kubota calls the PTO “independent”.


When using my bushhog I always use the clutch to let the blade “spin down” to a stop before disengaging the PTO selector.


It is possible I have just been imagining this but I don't think so! So if I may up your bet to a coffee and donut? I will double check mine also this afternoon.


Gary

 

[JKUB]

I am in full agreement with KennyV. A true independent PTO is unaffected by the transmission clutch. I own a L5030 GST and use the PTO for both a rotary cutter and tiller and I am positive that the clutch has absolutly no affect on the PTO.

GaryE; I did not check your bio to see what tractor you have but I am curious if it is perhaps an older model GST. I do believe that all Grand L 30 series tractors have a true independent PTO.

 

[GregH]

Two answers. On my L4310GST, the clutch does not affect the PTO.
On using the clutch, on GST's like mine, if you are running the Bushhog at say 2400 RPM and want to go in reverse you should use the clutch to avoid excessive driveline shock. On the newer ones with the computer controlled transmission, I understand the use of the clutch is not required.
The book on mine says to let the RPM's return to idle before changing directions or use the clutch.
FYI
Greg Harrison

 

[Dargo]

I am in full agreement with KennyV. A true independent PTO is unaffected by the transmission clutch. I own a L5030 GST and use the PTO for both a rotary cutter and tiller and I am positive that the clutch has absolutly no affect on the PTO.

No kidding? I have a L5030HSTC and the clutch definitely controls the PTO. If your clutch doesn't control the PTO, how do you slowly spin up the PTO? With my rotary cutter, if I spin it up too fast, one to the blades can get flung around backwards and cause a terrible vibration.

On the JD4600 I had, I always used the clutch when mowing to prevent the rear wheels from leaving any marks in my yard. Although I didn't technically have to use the clutch at all, I had considerably more control over the machine's movements.

 

[johnk]

On my 3130 GST I am almost 100 percent sure the foot clutch has nada to do with PTO. It even says in the maual to slow down engine RPM's and engage solenoid lever for PTO.

 

[KennyV]

OK it’s coffee (and donut) time…
On the L4200GST… It is a true independent PTO. The clutch has nothing to do with the pto.
Checking the WSM, and operators manual it states that, ‘PTO engagement without independent PTO needs clutch operation’…
with independent PTO there is no mention of using clutch but rather states, ‘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.’
I believe that this is the ‘feathering in’ process that allows the ‘controlled’ engagement of a true independent hydraulic clutch pack pto… I know I can start the heaviest, and also lightest, implement drive very slowly at any engine rpm by slowly moving the control lever.
Back to the origin of this post …
I don’t use my clutch, and haven’t for years… with the exception of 4 strokes on the foot clutch this afternoon… But that was not really for any particular ‘use’ … that was clutching for coffee… and maybe a donut.
… If your transmission clutch (foot clutch) has an effect on your pto, you do not have an independent pto.

Thank you to those that have confirmed what I have stated and
Thanks to everyone that has, and will check their pto and post the results. KennyV.

PS. I like black regular coffee, don’t care much for the new fufu stuff, and any type donut is fine, however I do try to avoid them.

 

[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