JD 4520 Hydraulic Issues.

[CoalWorker]

Context: Helping a church fix up their JD4520. We only have surface knowledge on how to work on tractors. It has a front Loader and rear equipment hooked up. According to them the Tractor has been sitting for several months. It has been maintained by the JD Dealer before.

What's Wrong:

• Front and Rear Hydraulic lifting movement is VERY jittery. It jerks up in a manner like climbing stairs compared to a smooth ramp.
• The pump whines and sounds like it winds up pressure and releases inconsistently, only then do the hydraulic lines actually jump slightly.
• The Power Steering is also inconsistent and works in pulses.

What We've Done:

• Changed the Trans/Hyd fluid filter and fluid.

Result: Tractor still behaves the same. We couldn't find the "Screen" former forums have discussed.

Additional info: Engine and other accessories all function well, the primary problems are have been isolated to hydraulic issues.

Question: What are we missing? We are seeking help by local farmers/tractor maintenance people for any advice.

 

[beenthere]

:welcome: to TBN

To confirm, this is the compact 4520, not the Ag 4520?

Hydrostatic transmission? or PowrReverser?

A picture of the tractor may help..

A pressure test of the various hydraulic ports may lead to the problem..

And can it be taken back to this dealer who maintained it before?

Parts can be found at the JD site
https://partscatalog.deere.com/jdrc/navigation/equipment/68742

Oil strainer as shown in parts.

 

[kennyd]

What was the condition of the fluid?
If it sat outside, there is a chance there is water in the hydro system and it grew algae that's clogging the screen (and filter).

 

[waycoolmarine]

what kind of oil did you put in the tractor ? is it deere hydro fluid ? and you need to clean the screen .

 

[CoalWorker]

It is a eHydro variant. It may be able to be driven to the dealer, but I'm uncertain.
The fluid we drained was very brown and sludge-like, including small chunks of unknown origin, once most of it was drained.
We put in Trans/Hyd fluid we bought from Tractor Supply Company, it was rated to be compatible with JD. We drained out about 9 gallons and put in enough to fill the oil line.
We are currently talking with other tractor owners who are guiding us as to where the screen is, we are going to attempt to reach it and clean it.

 

[beenthere]

it was rated to be compatible with JD.

Unfortunately, there is no enforcement or system to see that these claims comply for compatibility. So it is a "trust" that they know what is needed. The price difference is not huge, so when you do the next change (which should be soon when cleaning the screen) do the Low Vis Hygaard Deere oil.

Wish you good luck finding the screen and getting the system clean.. sounds like water leaked in or the tractor maybe was under water some. May have also come from pressure washing..

 

[kennyd]

The fluid we drained was very brown and sludge-like, including small chunks of unknown origin, once most of it was drained.

My guess is you still have a fluid issue and the filter/screen is clogged again.

 

[Ken]

The screen is the bottom of the transmission and has a hydro line of guessing 1 1/2 inch size going to filter. near the right tire and loosen 2 metric 10 bolts and if have not drained the fluid you just did. when the pipe is loose just pull apart held in place by a rubber seal. from the filter then reach in and remove the filter wash in diesel fuel. (once had a tractor brought to my shop for repair and had no power the screen was full of green or dried grass former owner failed to put fill cap on and mowed weeds with it.)
if the hydraulic oil has sediment or oily water maybe without running flush with diesel. also, I do not have any luck using other than John Deere fluid. 76 bucks a 5 gal. container if this clears the problem. system flush might be needed.

 

[Zebrafive]

The fluid you bought may be rated to an obsolete JD spec. My 46 year old JD 2030 took a different spec oil than my 14 year old JD 6415, but both get the latest spec JD HyGard.

 

[kennyd]

Just about any fluid is better than the "brown and sludge-like" fluid he took out, sounds like the screen was never cleaned so I'd bet it's jammed up.