Do you use a synthetic transaxle/hydraulic oil?

[tomrscott]

Is there a tractor transaxle/hydraulic fluid that is an improvement over the standard factory stuff?

With as dogmatic as some folks are about engine oil, I am surprised not to see more discussion of hydraulic/trans oil.

My JD790 recomends JDM J20D, Low Viscosity HyGard. I haven't priced it yet, but I'm soon going to be be dumping the oil to do a TNT installation and thought I'd research what I ought to put back when I'm done. We're talking 4 gal of oil if it all drained out, but I'm figuring a lot will remain.

 

[familyman]

Tom, I don't know anything about JD lubriccants, but I will tell you this. I switched from Kubota synthetic to a non-syn type trans/hydro oil and had a couple of problems. First thing the next mornining I noticed my hoe boom had lowered itself to the ground, which it had never done before (known as bleed down). Next, I noticed a distinct reduction in both response and power in the BH and FEL. This week I've been using the loader to move snow in single digit weather and it took at least 1/2 hour of use before the hydro fluid was warm enough for me to float my bucket on the driveway. The bucket control stick would not engage the float detent and bucket/arm movement was really slow.
There's been plenty of discussion on this topic, some of it heated, but I have seen the performance advantages of syn. v.s. dino firsthand and know what's in my future.
Go synthetic and don't look back! /forums/images/graemlins/cool.gif

Charley

 

[MikePA]

Two threads, same topic?

Amsoil Synthetic Tractor Hydraulic Fluid

 

[JerryG]

<font color="blue"> I'm soon going to be be dumping the oil to do a TNT installation </font>
Is there a reason that you are changing the fluid, when you are putting on the TNT?

 

[JohnDeereGreen]

I have an 03' JD X595 in which I use Amsoil Synthetic Tractor Hydraulic-Transmission Oil. This product is recommended for applications requiring the JD J20D spec.

Funny thing is just before Christmas I was cleaning my driveway and blew a hydraulic hose. I probably lost 3 to 4 quarts of fluid out of a 7 quart capacity system. I drove the tractor in the neighborhood of about 300 feet before I noticed the oil leaking. Then once I noticed, I turned the tractor around and backed it in the shed.

Dealer came to pick it up, fixed it, refilled the system with Amsoil (which I provided) and tested. No problems or issues. Still under warranty by the way.

Thank goodness for premium fluids. Don't know if any damages would of occured with the John Deere oil in there or not, but this does boost my confidence in Amsoil products.

Check out their website and click on product information at the top for the spec sheet on their ATH product.

Go Synthetic and don't look back. I also use the 15W-40 (AME) in the engine and one of their gear lubes in the front axle.

 

[rdln]

No, I dont use it never have but have used mobil one in cars but never exclusively in a car so no long term effects could be noticed by me. I guess I only dabbled with it.

I also recently experimented with hydraulic oil in the tractor using Mystik brand (trying to save a couple bucks)
this is the second drain and filter for the tractor and am not happy with cold weather effecting noise and performance 'specially in power steering.

 

[tomrscott]

JerryG,

Well yes, on the 790, the hydraulic system and transaxle are all one pool of 4 gallons of fluid. Probably that answers your question, but here's the process:

I have to tap into two hydraulic lines not counting the work lines that go to the new cylinders. This involves opening four ports that will have fluid in them ready to escape:

1) Open up the pressure line betweeen the Rockshaft PB and the FEL SCV P ports.
2) Connect the TNT SCV P port to the rockshaft PB
3) The TNT SCV PB port connects to the FEL SCV P port (this completes the circuit opened up in step 1)
4) Remove the line that connects the FEL SCV T to the crankcase to return low pressure fluid to the crankcase.
5) Replace this line with a new line that the TNT SCV tees into.

Generally speaking an open center selective control valve requires three ports not counting the work lines, pressure in, pressure out, and low pressure return to tank. When the valve spools are centered, the pressurized fluid comes in the P port and goes out the PB port. When I activate a spool, some of the flud from the P port is diverted to one side of a cylinder piston. As this causes the cylinder piston to move, low pressure fluid comes out the other port on the cylinder and needs to return to the tank (or crankcase in this case).

In the process of opening up all of these lines, I've got a choice, I can open them with fluid in the crankcase and try to quickly plug them and deal with the mess, or I can drain the crankcase first and make it a bit cleaner. The 4th step above opens up a port that is low enough on the crankcase to almost be a drain plug.

Making matters even worse, the bottom port of the return to tank line is completely covered up by all four of the FEL work lines leaving the SCV, so it looks like I will have to remove all four of those lines to get at the tank port, and then replace them when I am done.

On a system with a ready to go power beyond port, I suppose this process might be simpler, but on the 790 you need to tap into existing lines. /forums/images/graemlins/smirk.gif

 

[JerryG]

Tom,
From what you say, I guess that at least one of the lines that you have to break is lower than the mid point of the sump. I wasn't aware that any tractors were still coming in that way except the grays. Most have the connections at the top or the side of the top of the transmission. On those there is little to no fluid loss when adding additional connections.

 

[tomrscott]

JerryG,

For the pressure connections (P and PB), that might be true, but for the return to tank (T) connection it is almost on the bottom, which I guess makes sense.

Assuming those upper lines are above the fluid level point and the only one I would have to worry about is the sump connection, I might manage to plug it and deal with one "bleeder." I hadn't thought about the others being above the resting fluid level, but you are probably right. I might also have some fluid running back down out of the FEL work lines, but I can probably plug those too.

So the reason for the posting originally was just to speculate: If I am going to want to switch to synthetic, why not do it at the same time?

 

[cowboydoc]

For the tranxaxle and others that are a closed system I would probably favor the synthetics. They don't get changed often and there isn't much chance of contamination.

For the hydraulics I don't think it would be wrong at all to use synthetic but there are a couple issues here. No matter how good the oil is and no matter how long it will last it's a problem on hydraulics because of contamination. The hydraulics are constantly at risk for contamination and this chance is even greater over the winter when a tractor isn't used.

First is dirt contamination. If you even hook and unhook hydraulics one time you've introduced dirt to the sytem. Do that daily and you are going to have dirt in the system no matter how careful you are. Operate in dusty conditions and you're going to get contamination in the hydraulic fluid.

Second is water. Even with the best synthetic unless you are keeping your tractor in a climate controlled environment you are going to get condensation. This is probably a bigger issue than the dirt. There have been several studies done on this and everything I have read highly recommends that you change the hydraulic fluid every year, even if you only put 10 hours on your tractor. Because of this the cost for synthetics compared to a good dealer recommended oil it is probably not cost effective.

I don't think that with changing every year you are going to gain anything by using sythetics. Unlike start up wear on an engine if you let the tractor warm up properly that isn't an issue with hydraulics. If you operate your tractor without warmup you may gain something here but if the tractor is warmed up properly before using hydraulics I don't believe there is any benefit to the synthetics if you can't go on an extended drain interval.