Deere 4720 Hydraulic Drive Probelm??

[gkevin9]

Wanted to run this by you guys before I pay to ship off to the dealer:

This summer, my 2009 4720 has seemed to be "dragging" the few times i have used it. Top speed seemed to be down (would'nt get over 5.8 mph in B range).

It also seemed to run hot. Not the engine temp, but the trans. I had hot feet after about an hour of using it on a day in the mid 80's.

The last time I used it, it got progressively worse to the point where it started to greatly affect the steering (hard, jittery turn of the wheel) at which point I parked it.

I have no active error codes. I checked the trans fluid and it is clean and clear and at the right level when cold. Last serviced about 2 yrs ago. I probably use it less than 40 hrs a year.

The problem gets worse as the tractor warms up.

Any thoughts? Is there a filter that could be clogged?

 

[atsah]

Did you make sure you don't have a brake hanging up?

 

[oldtimer 66]

You could easily check the brakes out by jacking the rear of the tractor up, putting the range selector into neutral and applying the brakes. Then confirm that the brakes release by rotating the wheels/ left and right sides. The rear wheels should easily rotate without any drag. This is all done with the tractor turned off. You can do this cold and or after running the tractor to the suspected hot temperature. At the same time you can check for debris on the brake linkage that maybe holding the brakes on. You can also disconnect the linkage and confirm that the linkage operates freely. My second thought is that the load match switch is in the off position. This will affect drivability of the tractor. If the engine bogs down because of the Load Match switch is in the off position then this could cause the jerky steering at low RPM's. The Load Match switch is on the center console top left hand side. It's function is described in your owners manual. It electronically balances engine load and speed thru the transmission. How many hours are on the tractor? The hydraulic fluid and filter is to be changed every 400 hours. There is also a second small inline filter on the drivers side of the tractor under the floor board area, that needs to be cleaned at the same time the hydraulic oil and suction filter is changed. That's all I have for now. Later.

 

[oldtimer 66]

One other thing I forgot to mention on the hydraulic oil change is cleaning the suction screen. The best method is to follow the operators manual on the hydraulic oil change and not my memory. Later.

 

[gimmodog]

sound like it is a good chance that the suction screen is clogging

 

[Kyle_in_Tex]

Sounds like maybe your tranny fluid is getting HOT! This can be caused by the oil being forced through a valve or orifice that is "cracked" open just a hair. If you have a valve that you rarely use, check it to make sure it freely opens and closes, especially if it is cable operated.

How many hours on the machine?

 

[gkevin9]

Did you make sure you don't have a brake hanging up?

No, but I will. Thanks.

 

[gkevin9]

TO OLDTIMER66:

Thanks for the reply. 1900 hrs on the tractor. Fluid has 100 hours on it max. I will check the brakes. I have left the load match off before and it manifested itself differently than what I am experiencing now (but will double check!) After reading all replies I do suspect a clogged filter situation. I know I checked the inline filter under the floor boards last time. Process of elimination time so I will check the brakes and then replace both hydraulic filters. I don't live where the tractor is located (unfortunately) so it will be a few weeks or a month before I figure this out. I will report back, though.

 

[gkevin9]

sound like it is a good chance that the suction screen is clogging

Where's the suction screen? edit - I dont have the original OM but will look it up on line. Thanks.

 

[gkevin9]

Sounds like maybe your tranny fluid is getting HOT! This can be caused by the oil being forced through a valve or orifice that is "cracked" open just a hair. If you have a valve that you rarely use, check it to make sure it freely opens and closes, especially if it is cable operated.

How many hours on the machine?

1900 hours. Yes, it was definitely getting hot. It was on an 85 degree day but I still don't remember feeling so much heat from the trans before. Thanks for the thought. I will add it to the process of elimination list.