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Is slip clutch needed JD670

2194 Views 7 Replies 4 Participants Last post by  Ron JD670
I'm a new owner of an almost used JD670 (40 hrs)4WD geared I picked up a used 4' Rankin rotary mower from a local dealer. Nothing was said about a slip clutch, but, I have read some threads indicating it is recommended. Is one needed? I'll be doing some spring time road side weed control and bush wacking some new growth manzanita and buck brush for summer fire control. Ground is rough rocky but not steep. Thank you in advance for your thoughts.
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Slip clutch


It should already be protected with shear pins. Did the Rankin come with a manual? I like the idea of a slip clutch; but I hear they can also be a maintenance headache as they need to be adjusted properly. Hopefully other members who own slip clutch equipped implements will chime in.
I bought the Rankin RM used from a local dealer and had not thought to ask for a manual. They did show me the shear pin and in fact provided a spare. I will be finding out this spring about how often they break. I had read some place that without the slip clutch the spinning head could drive the transmission and thus the tractor even with the clutch depressed. Is this a real concern? The JD670 is about 2000#

Thanks for the help
Is slip clutch needed JD670 (or overrun clutch)

The "slip clutch" will not help with that problem, an "overrun clutch" will however, two different things for two different problems. I am 99% sure you 670 has a "live" or "independent" PTO. When you push the clutch in the PTO stays engaged correct?

Read this:

Thank you for the reply and link. Based on my short experience and reading the manual multiple time I feel certain I have a one stage clutch and based on the experiience with the PH auger both the PTO and transmission can be engaged/disingaged by the clutch - at the same time. The text in your link is almost exactly what I recall reading, although I do not recall any reference to the overrun clutch. Sounds like I need to make a test run in an open space with that rotary mower - low and slow - and see how the tractor responds. One more thing to think about while trying not to run over things I want to keep growing.

Thanks again.
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