Where is hydraulic temperature sensor on John deer 6400

Top of the differential housing, near the oil pump and to the right side.

Help in the link
https://www.google.com/search?q=John+Deere+6400+speed+sensor+location

There is a video for an 8300

https://www.google.com/search?q=john+deere+6400+replace+speed+sensor

Service Manual

https://therepairmanual.com/john-deere/john-deere-6400-6400l-6500-6500l-tractor-repair-manual/

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https://weingartz.com/assembly-diagram/john-deere-parts-lookup/model-2305-compact-utility-tractor-pc9501-hydraulic-pump-hydraulics/4275-176407-143985

I worked for Kubota for 10 years and I am not familiar with a PTO temp sensor, John Deere or otherwise. The PTO function has nothing to do with engine other than slight increase in coolant temp when the PTO is under a load. Check for correct Hydraulic oil level(dipstick or sight glass in transaxel) and make sure grass or trash is not packed around the hydraulic oil cooler in front of the radiator. Remove the screen and use compressed air to clean it often. Change hydraulic oil filters every 100 hours

hydraulic pump not working
filter to the pump blocked
valve stuck open

hi all jd info i get from their forum..well worth a look.
The Unofficial John Deere Forum

Hope this helps.

You can download the appropriate manual from the manufacturer's web site at
http://www.deere.com/servlet/com.deere.u90785.productcatalog.view.servlets.PublicationsSearchServlet?userAction=publicationsSearchResults&entryPoint=other&tM=FR&searchCriteria=6400&language=english&submit=Search

The temperature gauge is built into the instrument cluster and it needs to be changed as a unit.Try removing the wire from the temperature sensor and ground it to the frame of the tractor to verify that you do need the instrument cluster replaced,ground that wire will drive the gauge to hot if the gauge is good and nothing will change if it is defective.If grounding the wire made it work then you need a temperature sensor.Good luck and let me know how you make out!

Please email [email protected]. I would like to copy your technical and operators manuals, mine i think my x swiped, i really need them,,,,,,thx

miss delynda