722D Rear End Noise

dave61348

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I have a 2006 722D that is making a noise I just can't figure out so I'm looking for some help. The noise is coming from the rear of the mower and can be best described as a metal knock or a metal vibration. This has been intermittent and sometimes doesn't appear at all. It only happens with pto engaged and usually after mowing for a while. Possibly as something heats up? As soon as you shut pto off it goes away. I've checked everything I can think of with no luck. The mower has had a new clutch installed this spring and made the sound both before and after. I don't believe its a engine knock because I would think it would happen with deck on or off. The mower runs temp wise in the green and doesn't burn coolant. Oil looks good with no metal in it. I have checked motor mounts which look good. The mower does smoke a little more when this happens but I see no difference in power. Could a bad injector do this under load? Any input would be much appreciated.
 

cpurvis

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Check the bearings on the shafts that transmit power to the mower.
 

dave61348

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I've looked both front and rear bearings over and they seem ok unless I'm missing something. I grease those every third cutting. The mower has around 1600 hours on it so not sure what the usual timeline is to replace them.
 

qmark

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I've looked both front and rear bearings over and they seem ok unless I'm missing something. I grease those every third cutting. The mower has around 1600 hours on it so not sure what the usual timeline is to replace them.

Try releasing tension on the belt from the clutch and see if there is play in the idler or the shaft bearings. 1600 hours is significant.
 

dave61348

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Try releasing tension on the belt from the clutch and see if there is play in the idler or the shaft bearings. 1600 hours is significant.
I had actually replaced those late last year to try and chase the problem and that wasn't it. Could the clutch heating up cause that issue? I need someone to drive it so I can walk behind and try to pinpoint it. If I could guess I would say the clutch is making the sound. I had the dealer replace it this spring but the sound remains. The anti rotation finger doesn't show any signs of wear or metal to metal contact. I did record a short video of myself driving it with the noise very noticeable. If it would help I could post the video.
 
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