[denverguy]

I am guessing that OP was planning on using this: CASE IH | Hy-Tran® Premium Hydraulic Transmission Oil - Synthetic - 5 Gal./18.92 L | 73344275 | MyCNHi US Store

It is synthetic. OP thinks it is better than all others. I have no data to support or deny that thought. It isn't clear what weight it is or how well it would work. For a K46, R&R of the transaxle plus the fluid change is a decent amount of work. The cost of the fluid would be relatively small compared to the time (unless you work for free/fun). I value my "free" time at -$50 to $50 or more/hour depending on how much or little I like doing something. For things I hate doing, paying someone $50/hour it would take me to do it is easy. For things I really like doing spending $50/hour might be just fine. Replacing transaxle oil is not something I like doing, but I don't hate it either. So $15/hour is not bad. So spending $40-50 on oil instead of $20, would be easy if it saved just one oil change.

I highly suggest the TuffTorq synthetic route

But it's not what TuffTorq recommends.

 

[Benz88]

From what I was told by other coworkers the Low-Visc Hygard is a 10w40 synthetic with a friction modifier added to it. I have no proof but this is what I was told. Deere also says not to service them

 

[arlen]

The old adage "You learn something New every day" certainly continues to ring true throughout my life.

After doing more research on this, I have found plenty of eg's of large mining and other commercial heavy diesel operations that use 15/40 diesel motor oil in place of hydraulic fluid. Although, most of these were simply seeking a more cost effective/ convenient method of only having to stock One type of oil. Never the less, if there would have been a significant cost to pay in greater maintenance or break down, I'm sure this is where it would have been seen.

Growing up and being mechanically inclined from a pretty young age, I always respected that the correct fluid needs to be used in the correct application. Understanding that hydraulic fluids, trans fluids etc, could have some interchanging because the applications are all Hydraulic. Brake fluid for eg. being at the Top of the list and not being able to be replaced by anything else. (although I do remember some telling me you could get away with trans fluid in an emergency, but not sure I ever bought that)

I Never heard of motor oil being referred to as a hydraulic fluid and have always separated it from the possibility of being used as such.

After looking further into this though, it would seem that I have been ignorant of the fact that All fluids to some extent are considered hydraulic, simply from there ability to be compressed without breaking down and loosing all volume.

So my over all views have shifted about this, which is also the reason I posted this up originally. I have found that by posting something and seeking scrutiny from others, and as long as you can remain open minded and unoffended, you will most likely come to a greater understanding of what you seek. Whether you are right, wrong or indifferent, is really neither here nor there, as long as the Truth is able to prevail, or at least your ability to understand what part of it you can at the time.

It makes sense to me now, that the reason for running motor oil in these trannies could simply come down to Heat. If the #1 failing grade is from to much heat, breaking down the hydraulic fluid, then motor oil shows a clear advantage, as it is meant for a much higher temperature resistance than hydraulic fluid. Also, and I'm not sure if this is still true today, but hydraulic fluid was not available in a 50 weight. So again, if too low viscosity is the issue, then motor oil covers that better as well.

Why JD seems all over the map on what they recommend, across the years and models still seems strange though. I would have thought it would have more to do with regions, like with some vehicle manufacturers back in the day, running lighter viscosity fluids in manual trannies in Canada because of the colder winters.

Make no mistake, IF I lived in Texas, I would be telling you all that my plan is to run 20/50 full synthetic motor oil, and it would have been that even before I knew what I know now.

However, I live in Canada where we rarely see temps in summer reach 90 deg. Usually mid 70's or cooler. So I'm still inclined to consider the Hy tran as a viable option.

I think you have a good enough understanding. Pretty much the same thing I learned when I bought a John Deere skid loader a few years back, and wanted to do a fluid servicing. For cold weather operation, the manual recommended the JD 0w40 in engine, hydraulic system, chain case and engine. To the tune of 25 gal
My regular ag dealer said they were still putting engine oil in them when they service them. I stopped in the JD construction dealer, and they clued me in about the zinc being greatly reduced in the modern diesel oils (probably due to after treatment). So they told me about the Hydrau XR, which was made to replace engine oil in the tranny and chain cases of their construction equipment (including skidloaders). It has zinc in it for anti wear. Makes me wonder if it would be better in the engines (without after treatment)😂

One a side note, I believe Hygard is also specified for replacing engine oil in hydraulic applications calling for motor oil.

 

[Frogmore]

it's not what TuffTorq recommends

I agree with you. TT now recommends their "special" fluid. Is it really better for the customer or does TT make money on it, which is why it is better. Is the Hy-Gard LV better for the customer or better for Deere, since they make money on it. Is Hy-tran really better as @GreenDream is convinced, perhaps because he is a Case fan? I am pretty sure the K46 would run fine on any reasonable hydraulic fluid for a few hundred hours and likely longer under normal conditions.

 

[flyweight]

Why engine oil instead of proper hydro fluid in JD trannies?



The main reason is, when used in a small application (small space with low quantities) engine oil is "Non Foaming".

 

[mo1]

From what I was told by other coworkers the Low-Visc Hygard is a 10w40 synthetic with a friction modifier added to it. I have no proof but this is what I was told. Deere also says not to service them

Deere's oil guide states that low-viscosity Hy-Gard is ISO 32 and regular Hy-Gard is between ISO 48 and 64. Low-viscosity Hy-Gard is 32 centistokes (cSt) at 40 C and regular Hy-Gard is 59 cSt at 40 C. A 10W-40 oil would have a viscosity at 40 C of about 100 cSt so it would be noticeably more viscous than low-viscosity Hy-Gard. Regular Hy-Gard is similar to 10W-30 and low-viscosity Hy-Gard is similar to 5W-20.

 

[GreenDream]

Just to add to this for anyone in the future wanting the inf;

Tuff Torq themselves state that the only reason JD decided to go with 10w30 motor oil and no drain plugs was for cost saving. So that is out of the way.

I would add to that, JD most likely figured that in 95+% of the applications the 10w30 motor oil would be fine, and seems they were correct.

Tuff Torq recommends;

First, Their Synthetic hydro fluid which is 5/50 weight

Second, JD Hygard high visc synthetic

Third, 5/50 or eqivalent full synthetic motor oil

I believe the visc of the Hytran is like a 10/30 oil from what I've read. I've had great success with it which is why I keep stock around. The fact that I have it here at my disposal is the #1 reason I thought of using it over synthetic motor oil.

As @Frogmore has stated (and several others), and I agree 100%, any of those selections will most likely do just fine. (Any are much better than the factory filled dino 10/30!)

 

[RalphVa]

I'm looking at a JD D160 right now and if I pull the trigger, first thing I will do is crack open the K46 and full service with drain plugs etc.

My first inclination would be to use Hy-tran fluid, which has proven to be the best hydrostatic And Auto/ manual transmission fluid I have found.

So why would Tuff torq use 10/30 motor oil? I understand why you would switch to 5/50 or even 15/50 full synthetic, but the Lizard brain is telling me the Hy-tran would still be Far superior in almost every respect.

Has anyone else struggled with this, and are there any out there that have gone to a superior hydrostatic fluid vs motor oil?

The mechanics in our refinery always used motor oil in the hydraulic drive units of our big rotary filters. Works but over use of detergent additives, etc.