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Dan, Technician
Category: Agriculture and Farm Equipment
Satisfied Customers: 5183
Experience:  17+ yrs. shop and field experience with all major brands of heavy equipment, trucks and farm equipment - 1995 WyoTech graduate.
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7720 deere combine four wheel drive (mudder) is blowing oil

Customer Question

7720 john deere combine four wheel drive (mudder) is blowing oil out the relief valve on the drive motor. How can I fix this.
Submitted: 1 year ago.
Category: Agriculture and Farm Equipment
Expert:  Dan replied 1 year ago.

Hi Lanny, My name is***** will be glad to try to help. Is it blowing oil just out of the relief valve cartridge itself? If so, one of two thing is happening. Either your drive motor has failed with excessive internal leakage and case drain pressure or the relief has failed. Try swapping a good relief from the other drive motor to see if the problem resolves for test purposes. Also check for metal in your return filter indicating a drive motor failure and test your case drain by running a hose into a bucket with the travel motor deadheaded to prevent movement an slowly engaging travel... should be low volume of case drain oil

Expert:  Dan replied 1 year ago.

If it comes out under high pressure that drive is bad. Let me know

Customer: replied 1 year ago.
I had already replaced the relief valve with a new one, also changed the filter in the reservoir tank. I have not had time to check the case drain. I assume I disconnect the case drain hose from the valve under the combine and leave the hose connected to the drive motor then see if oil comes out the hose when engaged..
Expert:  Dan replied 1 year ago.

Yes you would run the hose into a bucket. I usually clamp a hose onto the drive motor case drain fitting if the other end is not accessible. It is supposed to be very low volume and pressure unless the motor is bad and then it can spray out.

Expert:  Dan replied 1 year ago.

Hi, Did you get this resolved? Please remember to take the time to rate my service as that is how the experts get credit for their time helping on the site.

Customer: replied 1 year ago.
Today I had some help. I disconnected the case drain hose from the valve under the combine. Cranked the combine engaged 4X4 .
Oil shot out the case drain hose in a stream the size of the hose. Oil also shot out the relief vale. Oil also came out the valve where the case drain connected to. Back to square one.