[GreenDream]

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?

 

[jgayman]

You can never go wrong with using the fluid recommended by the manufacturer.

 

[JimR]

Why over think it?

 

[Old Machinist]

AND you are likely to drain a working transmission and end up with a non working unit.

 

[Frogmore]

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.

I looked it up Hy-tran is a conventional oil/fluid, ie not synthetic. The K46 is an entry level transaxle. Putting the "best" oil in it won't make it any better. Just like drinking the same sports drink elite athletes do, won't make you perform at their level.

I think you can safely assume the engineers have done some work to determine what works best in their creation. But, you are free to disregard it and assume you know better. I am reasonably certain that your results will likely be the same either way.

 

[tsoleno]

Deere seems to recommend there low vis for some reason. TT has their own, but say it is acceptable to use either 10w30 or 5 /15w50 synthetic. I use the Vanguard 15w50 when I change them, but am in a warmer climate. I see no reason why you couldn't use the Hy-tran myself.

 

[GreenDream]

Appreciate the comments, and I'm just thinking out loud about this, nothing set in stone.

Correct me if I'm wrong, but don't all the serviceable, higher end hydrostatic trannies use proper hydrostatic (Hydraulic) Fluids?

I will have to do some reading on how these trannies actually operate, but just seems weird if they do rely on pressure and staying Cool, that any motor oil could possibly work as good as a proper hydraulic fluid. Not to mention sheer stability and a number of other factors.

 

[Longhorn_007]

It's not exactly apples to apples, but the new gen woodmaxx chippers with hydraulic infeed require engine oil (conventional, not sythetic) and they specifically say not to use hydraulic oil. It's just what the pumps were designed around, and I would very much recommend against ignoring the manufacturer's specs and requirements. At best, you might find that the performance isn't as good (more fluid slipping past the rotors thus less torque) and at worst perhaps actual damage.

 

[Frogmore]

Generally speaking, the base of motor oil and hydraulic fluid is the same, oil. There are differences in oils and there can be large differences in the additives. These additives can cause problems if the wrong ones are in place. How quickly the problems occur probably depends on the additives and the transaxle needs.

Here is an example of what happens if you replace engine oil with diesel (which is better than replacing it with gasoline)

This Is What Happens When You Replace Your Engine Oil With Diesel Fuel

Cleetus McFarland bravely finds out just how far this engine will go when replaced with diesel fuel.

www.hotcars.com

Its your transaxle, so do what you want. For my K72 and K92 I use the Deere recommended Hy-Gard Low Viscosity Fluid, even though I "know" it is not the best fluid. For my K66, if I ever get around to installing it in my X300, I will use 5W-50 full synthetic, since that is what TT says is the best for their transaxle. But, I doubt that I would get different results from using your favorite fluid (or SAE30, or Hy-Gard LV) with the usage I am likely to have. It doesn't really matter that much. What does matter is having enough, clean enough, oil/fluid. I guess the real question is how much are you willing to bet you know more than the manufacturer is telling you? The K46 costs several hundred dollars. It will either last long enough or not. Your choice of oil might switch it from one to the other. If you are sure it will switch it to long enough (or definitely not switch it not long enough) I don't see any harm in your plan.

 

[jgayman]

Generally speaking, the base of motor oil and hydraulic fluid is the same, oil. There are differences in oils and there can be large differences in the additives. These additives can cause problems if the wrong ones are in place. How quickly the problems occur probably depends on the additives and the transaxle needs.

Its your transaxle, so do what you want. For my K72 and K92 I use the Deere recommended Hy-Gard Low Viscosity Fluid, even though I "know" it is not the best fluid. The K46 costs several hundred dollars. It will either last long enough or not. Your choice of oil might switch it from one to the other. If you are sure it will switch it to long enough (or definitely not switch it not long enough) I don't see any harm in your plan.

Current price from JD for the K46 is $923.

 

[ironpony]

I have commercial hydros on my ZT and they use 15-40 engine oil, I always thought it was weird but the manufacturer has their reasons.

 

[Red badger]

My thought is the proper oil is what the manufacturer recommends, not all hydrostatics are the same. The older ones are designed much different than the newer ones.

 

[GreenDream]

My thoughts on this are along the lines of a few of you who have said you see no downside. (other than cost, as the full synth Hy-tran is pricier than oil)

I have had many friends and contacts that have worked behind the scenes in manufacturing and 9 times out of 10 or more, it simply comes down to the most cost effective thing that does the job. Having thought on this over the last day, wouldn't surprise me at all if that isn't exactly the case here.

If 10/30 motor oil is going to do the job for the life of most of these tractors for what owners are using them for, why would you use a fluid that over the millions produced, will cost you millions more? Vs Making millions more. Answer is simple, you wouldn't.

Even if tests showed that a high end fluid gave 15% more longevity, the 85%, if it meets the criteria and because of the cost benefit, would win out.

I am a firm believer in Mobil 1 full synthetic and have used it exclusively in my low 10 sec race car for 20 years. So I have no issue running it and IF the trans was sluggish or suffering any illness before it came apart, I would go 5/50 or 20/50 just for the higher viscosity and that it's been proven to work.

I have also, from personal experience, seen Hy-tran out do Mobil 1 in a standard transmission in that same 10 sec car, so I am also a believer in it's superior lubricating abilities.

Having said all of this, the Hy-tran is a full synthetic and about 30 weight, so up North where I come from winters get Mighty cold. Heat, that is most likely the killer of most of these smaller units, Not so much a problem.

I guess I won't know until I see if I get my hands on this one. Obviously if I do, it will be in proper working order.

If I crack the trans open and it's nice and clean inside with little debris and all looks well, I will most likely use the Hy-trans. As several of you have reasoned, there is no downside. At the very worst, I spent a little extra for nothing.

If, on the other hand, I see lots of fuzz on magnet and dirty oil and get the feeling it has had a hard life, I may just go with a 50 weight and call it a day.

 

[arlen]

JD has a hydraulic oil to replace where engine oil was called for. It’s called Hydrau and Hydrau XR. John Deere skid loaders until very recently called for engine oil in their hydraulic systems and even their chain cases. They wanted one oil for everything on their construction equipment.
They said engine oil with its additive package and detergents made great hydraulic oil until they started having to chop the amount of zinc because of exhaust after treatment stuff came along. Zinc I guess is a good anti wear additive for hydraulic and hydrostatic components. So the Hydrau is high in zinc.
So that’s construction equipment, but your application is different. Still maybe something to consider

 

[mo1]

Regular (J20C) Hy-Gard is about 10W-30 in viscosity, but the additive package may differ quite a bit from a gasoline engine oil, a diesel engine oil, or a dual-rated oil. Whether or not that makes it a better or worse choice would probably require the input of an engineer that worked on this kind of drive. It is certainly possible that Hy-Gard could be a better choice but the third-party manufacturer of the hydrostatic drive just said to use 10W-30 engine oil rather than specifically call for a product sold by only one of their customers.

I will say that 10W-30 sounds a bit light on the hot viscosity for hydrostatic oil in a mower. My mower has a set of Parker drives that call for 5W-50 synthetic.

 

[GreenDream]

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.

 

[Frogmore]

From a dictionary:

denoting, relating to, or operated by a liquid moving in a confined space under pressure.
"hydraulic fluid"

Hydraulic means you have a liquid.
Hydrology usually means water related.
Hydro means the power company in some locations (as in BC Hydro) typically because they have water powered generators.

The base fluid in most hydraulic fluids AND motor oil is mineral oil. Mineral oil is a liquid by-product of refining crude oil to make gasoline and other petroleum products. There are differences in the viscosity and the additives. There are additives than can change the viscosity and friction characteristics. There are also "snake oil" like claims from some people.

Use Hy tran if you think it is best. It is probably just fine and it is unlikely to cause an issue in the timeframe/usage you are likely to care about.

For the K46, I would use 5w-50 full synthetic, which is what they now recommend. The other choices are SAE30 or Hy-Gard Low Viscosity. All of those have been recommended by someone in the past. I use Hy-Gard LV in my K72, because that is what was in there to begin with and I don't think it matters much either way.

 

[Spencer]

Thankfully the Hydro Gear ZT4400s in my Ferris ZTR specify 20w-50 synthetic motor oil. I've heard from multiple sources that Hydro Gear fills them with Mobil 1 15w-50 which is readily available for around $8 per qt and it's what I've been using, I think it requires 9 qts. One brand ZTR I was considering, I can't recall which but back when I was looking to buy, insisted that only their brand hydraulic oil should be used and naturally oil with their name on it it was very expensive.

 

[denverguy]

I highly suggest the TuffTorq synthetic route for a simple reason, synthetic breaks down at a higher temp than conventional oil. I'm sure you've read the horror stories of the failed K46 transmissions. Sure, the K46 has a long life if used as designed, but with relatively low power ratings, they are easy to overload. The first sign you have been overloading it is when the tractor will no longer climb a slight grade. Pushing the hydro beyond its (low) design limits generates more heat that can degrade conventional oil.

While I tend to use synthetic across the board, I recognize the difference is marginal in most situations. In this case, my recommendation to use synthetic is strictly due to its higher breakdown temp.

Why not use synthetic and have a higher margin of safety?

 

[Frogmore]

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.