JD 4720 Hydraulic Failure

[blackfalcon]

Hey guys. I have a Deere 4720 less then a year old with about 265hrs on it. I haven't drove it much when it was cold. I briefly drove it the other morning when it was around 30 out and I noticed hydraulics seemed to be running a little slow/sluggish. I went to drive it this pm and spent approximately 10 minutes on it. I noticed the hydraulics were running slightly sluggish again, almost like if the fluid was low (which is what happens on my 2720 when its low). I went for a second scoop of loose dirt, the tractor stalled out. I restarted it, and was unable to move bucket, steer, go back and forth etc. etc. Basically complete hydraulic failure. I check fluid and it was right at the top of its range etc. Am I missing something simple that would cause all the hydraulics to fail? Is there anything I should check before calling the dealership.

 

[arlen4720]

The suction screen would seem most likely.

 

[wmonroe]

Suction screen is a good idea. Have the filters been recently changed?

Maybe the relief failed and is letting all fluid bypass?

 

[Red Horse]

IMO no way could this be a dirty oil issue-with those kind of hours I would be standing on the dealer's desk right now-not your problem-that is why we pay the big bucks for that green paint!

 

[arlen4720]

I would definitely focus on the suction side of things...that's the only common denominator. There are 2 separate pumps (3 counting the hydrostat), so 2 separate relief valves. The power steering pump supplies charge flow to the hydrostat pump. There is a short chunk of suction hose near the pump set also, you may want to look at that too. I suppose that the pump drive coupling could have sheared, but I hope for a suction screen or filter.
I would let the dealer handle it.

 

[blackfalcon]

The pump drive shaft sheered off from what I was told by the JD dealership. They ordered the part and will be back in business Friday.

 

[cartod]

I love happy endings.

 

[wmonroe]

Was it a manufacturing defect, or something that caused it, or just bad luck?

 

[J_J]

I am not seeing how one pump caused total hyd failure.

A dead implement pump would not affect the transmission.

If it has a steering pump, it should still work.

 

[coobie]

The pump drive shaft sheered off from what I was told by the JD dealership. They ordered the part and will be back in business Friday.

Glad to see ya up and running