Over-running coupler size

[canoetrpr]

I'm looking into getting an external over-running coupler. I've got a Kubota L3400.

Looks like there are a few different sizes available and just thought I'd check here to ensure that I do order the right one.

I *believe* what I need is a 1 3/8" female 6 spline in and 1 3/8" male 6 spline out. I assume that this is a pretty standard PTO size.

Is this correct?

 

[Soundguy]

Yep..

Soundguy

 

[BobG_in_VA]

I'm looking into getting an external over-running coupler. I've got a Kubota L3400.

Looks like there are a few different sizes available and just thought I'd check here to ensure that I do order the right one.

I *believe* what I need is a 1 3/8" female 6 spline in and 1 3/8" male 6 spline out. I assume that this is a pretty standard PTO size.

Is this correct?

Duh???Are you saying that the Kub L3400 doesn't have live PTO??? Originally, the Over Running Coupler was for tractor PTOs that run off the trans,,,like a Ford 8N....BobG in VA

 

[canoetrpr]

Duh???Are you saying that the Kub L3400 doesn't have live PTO??? Originally, the Over Running Coupler was for tractor PTOs that run off the trans,,,like a Ford 8N....BobG in VA

There is in fact a method to my madness

The L3400HST has a live pto with an internal over-running clutch. The ORC and the PTO engagement CAMs are one and the same thing actually.

There has been the odd report (one or two) on this board of the PTO cams being worn to the point of not engaging anymore (thats what was understood to be the cause in that case anyway).

On newer models of the L3400, Kubota has made a running production change and changed the PTO cams to be "solid type" - i.e. they just got rid of the over-running action of the cams.

I know not why they thought and ORC was necessary anyway as once the HST pedal is centered the tractor isn't going anywhere regardless of the momentum from the implement... but I'm no expert on PTO cams.

Long story short, almost all L2800/L3400 HST owners here have managed to get their PTO cams replaced with the new "solid type" cams that are being shipped in the new tractors. There is a bullieten from Kubota to dealers that outlines this change (although only in reference to the 'noise' that the internal ORC makes).

Up here in Canada, I'm having some grief getting the cams changed... won't go into the details.

If I don't manage to get these changed under warranty, I figure there is no harm in me getting an external ORC to ensure that when I clutch to disengage the PTO, it freewheels the implement and so the internal ORC never has to rachet.

I should point out that the internal ORC / PTO cams are imbedded deep into the tractor - changing that requires splitting the tractor.

Make sense?

 

[canoetrpr]

BTW, no one has yet tried to explain (to my knowledge) what makes the internal ORC suddenly unnecessary.

After all someone during initial design did think that absorbing the inertia from the implement when the clutch was depressed and before the PTO lever was moved to the OFF position was desirable.

Feel free to speculate.

Someone on the thread regarding this issue suggested the external ORC as cheap insurance. Seemed to make sense to me.

Here is the service bullieten that shows the pictures of the old and new cams.

 

[Soundguy]

Bring me up to speed.. is this tractor one of the few that are HST.. but DO have a clutch pedal?

In most cases, HST tractors have independent pto's.. and thus don't need ORC's.. unless you want to save the PTO break ( not a bad idea mind you.. ).

With an hst tractor.. I'd ahve a hard time seeing the unit not having an independent pto.. and in that case.. i don't see where rotary inertia could be transmitted to the wheels.. etc.

Soundguy

 

[canoetrpr]

Hi Soundguy. Appreciate your thoughts on this.

The L3400 is indeed one of those that is HST but does have a clutch pedal. It has live PTO rather than independant.

When the tractors clutch is depressed while the PTO lever is in the ON position, the internal ORC rachets.

The internal ORC is built as part of the PTO cams (you can see this in the pictures in the link I posted above). The opinion on the Kubota forum has been that an ORC such as this built into the PTO cams is a bad thing because when it wears the PTO will not engage any more and replacing the PTO cams requires splitting the tractor.

Kubota changed this PTO cams design and completed eliminated the over-running action of the cams in newer L3400/L2800 tractors.

Honestly I don't really know what to think but I have not managed to have the PTO cams changed to the new ones without the over running action. I'm thinking that using an external ORC and letting that wear when I depress the tractor clutch is much better than letting the PTO cams wear.

If I do manage to get the PTO cams changed to the new style like others have I still have a hunch that I am better off for having an external ORC anyway. Obviously someone at Kubota designed a ORC onto the PTO cams for a reason and now has decided to eliminate them.

What do you think?

 

[AlanB]

Bring me up to speed.. is this tractor one of the few that are HST.. but DO have a clutch pedal?

In most cases, HST tractors have independent pto's.. and thus don't need ORC's.. unless you want to save the PTO break ( not a bad idea mind you.. ).

With an hst tractor.. I'd ahve a hard time seeing the unit not having an independent pto.. and in that case.. i don't see where rotary inertia could be transmitted to the wheels.. etc.

Soundguy

Been a while, but there was the same thing with the NH TC33's I think and particularly my NH 1925

It was discussed at length on the NH boards, and I do not remember why it was occuring, but thought it cheap insurance to pick up the ORC.

Will probably show on a search of the NH boards.

 

[Soundguy]

Wow.. I'd prefer a 2 stage clutch to that hokey orc/ live hst pto setup.

In any case.. yeah.. I'd slip on a 60$ orc on the back and not worry about the innards of the tractor detonating due to bad design..

soundguy

 

[RickB]

You are looking for 1-3/8" six splines on both output and input; that's for sure. The bad news is that from my experience with internal sprags on New Holland compact PTO drivelines, they fail from use under load, not freewheeling to a stop. Purchasing an external ORC may very well not extend the life of your internal ORC, or sprag, as I refer to it.