John Deere Z820A with Parker Hydros. Use J20C or J20D??

Joined
Jan 29, 2016
Messages
18
Location
Ohio
Hi there.
I have a JD Z820A Zero Turn mower with 430h. This design was plagued with more than a few user experience and control issues. Basically, the ZT, specifically the hydros, left a lot to be desired out of the box resulting in an update campaign and even some dealer buybacks.

I've read various things that dealers have done to try and remedy the almost skid-steer like control experience.
There have been pulley updates, steering damper updates, release valve updates, etc.
One that really stuck out to me was an instance where an owner shared that the dealership replaced the High Viscosity (J20C) Hy-Tran with Low Viscosity (J20D) and they had fantastic results.

There are various points in the manual that says NOT to use low-viscosity in the hydros. I am attaching the sticker from my mower that shows this. Its possible I have an early rendition.

I called a JD Dealership and the parts person said they don't know why they would ever spec for this application and suggested the lower viscosity stuff.
I am torn as to what I should do. I am merely hours away from my hydro change and would like to remedy the drive-ability issues that I certainly feel. They tend to go away by the end of my mowing session but that's HOURS and take a good while until I feel like the oil is warmed up or whatever it needs to do.

Parker, the manufacturer of my hydros in this unit has their own oil-Parker HT-1000. Its pricey.
What do you think I should do?? Are there considerations I may be missing?

This hydro setup exists in other brand mowers and does NOT have this usability issue reported by JD owners. I can only assume the issue is oil related. Is that a fair assumption?


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That parker fluid looks pretty thick its no where near Low-vis hygard
So I would stick to the J20C
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I'd do it. Most of the newer stuff shows J20C as preferred but lists J20D for cold weather applications. If the hydraulics are crap already what's it going to hurt? My Gator shows J20D for the diffs and the trans. That seems crazy to me but if it can stand up to a gear box and a differential gear set in 4x4, it should protect your machine just fine.
 
OK. My worry is wearing the hydro out with inferior oil. I'd like to try the low visc to see how it feels. Mower is a different machine after its warmed up... does oil flow easier when warm? Is the final viscosity the same?
 
Oil gets thinner as it warms up.

That Parker HT-1000 you listed earlier the specs are
126cST @40 degrees celcius
13.25cST@ 100 degrees celcius.

Typical viscosities for deere brand hygard
J20C 55@40c 9.4@100c
J20D 33@40c 7.1@100c
 
What do you suggest I do? I'd like to try thinner oil to see if the controls smooth out. I'm worried about screwing up the hydros, though. I wonder what the other mowers that have these hydros use for oil.

Use the J20C?
 
Hi there.
I have a JD Z820A Zero Turn mower with 430h. This design was plagued with more than a few user experience and control issues. Basically, the ZT, specifically the hydros, left a lot to be desired out of the box resulting in an update campaign and even some dealer buybacks.

What do the "updates" include? I am wondering if there is a service bulletin for your machine, or an updated recommendation for the hydro fluid.
 
Pulley changes. Damper update. Weight kit for rear. Hardened valve seats on hydros for bypass.
 
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