# Over running coupler



## 19442N (Apr 14, 2018)

Over running couplers. Are you guys using them and do they stand the test of time? I stood tall on the brake but still took out the trash can.


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## sixbales (May 18, 2011)

On the old transmission-driven PTO's, an over-running coupler is important to prevent the rotary momentum of the PTO implement from driving the transmission when the clutch is depressed. These are time-proven devices, been in service for many years.


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## pogobill (Jan 31, 2012)

I'm with sixbales, it's a matter of safety!


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## 19442N (Apr 14, 2018)

Thanks men. I'm thinking that since the PTO shaft needs a rebuild I'll just replace it with a conversion shaft and the coupler. Do you guys have to shorten a drive shaft when coupler is installed?


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## sixbales (May 18, 2011)

You may have to shorten the shaft when you install the conversion shaft and coupler. After the installation, check that your shaft still has capability to slide inwards so that you do not impose compressive force on your PTO system in the tractor.


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## RC Wells (Dec 26, 2008)

If you replace your PTO shaft with the new larger version, you will also need to change the yoke on the rotary mower drive shaft to match the larger diameter PTO. 

Because the overrunning clutches bolt directly to the PTO, and unless the PTO spline is worn to the point of being sloppy, I would just get a clutch in the original 1 1/8" size and LocTite 660 to eliminate any micro-movement in the PTO spline to clutch union. 

Usual slop on these systems will be found in a worn driveshaft yoke, as it is a softer material so it is sacrificial over time and not chew up the PTO itself from dirt in the union.


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## 19442N (Apr 14, 2018)

RC Wells said:


> If you replace your PTO shaft with the new larger version, you will also need to change the yoke on the rotary mower drive shaft to match the larger diameter PTO.
> 
> Because the overrunning clutches bolt directly to the PTO, and unless the PTO spline is worn to the point of being sloppy, I would just get a clutch in the original 1 1/8" size and LocTite 660 to eliminate any micro-movement in the PTO spline to clutch union.
> 
> Usual slop on these systems will be found in a worn driveshaft yoke, as it is a softer material so it is sacrificial over time and not chew up the PTO itself from dirt in the union.


The previous owner was using a spline adapter on the PTO shaft. So I thought by installing the conversion shaft it wouldn't be necessary to replace yoke. Please correct me if I'm wrong. Thanks.


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## RC Wells (Dec 26, 2008)

Should be standard yoke then.


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