# 1973 john deere hyd oil over heating



## demon (Jan 28, 2021)

i have a new to me 1973 john deere 401a loader ,the hyd fluid is getting red hot on the control levers,my questions do you drive the tractor with the pto engaded without an implement. thanks


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## pogobill (Jan 31, 2012)

Welcome to the forum. I don't think anyone runs the pto unless the is a use for it. If there is no implement attached, there is no point in running the pto. Besides, that could end up being downright dangerous if you caught a pant leg or a sleeve in it!
I take it you are, and your oil is hot?


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## Tx Jim (Jul 28, 2020)

Yes your tractor could be operated with pto engaged with nothing attached to pto shaft. JD offered a pto shield for that purpose. My guess is a high pressure internal hyd leak is causing hyd oil to get hot. I suggest to check all hyd control valves with a laser thermometer & take note of control valve with highest temp.


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## Cvans (Sep 7, 2008)

That last time I heard of hydraulic oil overheating it was because they were operating it with the wrong oil.


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## Tx Jim (Jul 28, 2020)

Cvans said:


> That last time I heard of hydraulic oil overheating it was because they were operating it with the wrong oil.


There are many other reasons for hyd oil to get hot other than incorrect type hyd oil especially on closed center hyd systems such as this tractor. Relief valves not holding system pressure, open center valve connected to CC hyd system & as I previously stated internal high pressure leak are more common causes for hot oil. Demon needs to perform very good diagnostic procedures to locate the heating problem.


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## Cvans (Sep 7, 2008)

I'm aware there are other reasons. This is just an option that is seldom brought up.


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