TO-35 Transmission Oil

Hi Everyone,

A while ago, I posted a question regarding using gear oil or hy-tran fluid in my TO-35's transmission. I got the message about using a GL-1 oil. It looks that oil is available in 80 or 90 weight. I understand the distinction about using one vs. the other depending on whether the temp is above or below freezing. My question is, can I use the 80 weight year-round? Will it be hard on the transmission? My usage for the tractor is pretty light, generally. Or, do I need to change out the oil each season? Seems like 8 gallons of oil, twice a year would get expensive after a while. What about a synthetic oil like Slick-50? Thanks for your opinions!

Just use multi-grade 15W/30 oil all the year round. It is thin enough for really cold weather and fine for summer temperatures as well. Forget the GL1 type oil now the Multi-grades are much better for your tractor.Regarding changing the oil, it does need to be changed every 12 months as it deteriorates, just even standing and it will collect water that needs to be flushed out of the system, if you don't that will cause you problems, so it is cheaper to change the oil than leave it.....John

That sounds like a good solution! Thanks, John!

i thought the issue was that Gl-1 oil would protect the bronze bearing in the transmission.

Other oil would not protect these bearings.

Gl-1 has protected my tractor transmission for 52 years and its still running fine. Why would you want to take a chance on messing up the transmission bearings.

either oil will work fine for the hyd system, but that is not the issue.

napa has the Gl-1 oil at a reasonable price.

Just curious, where have you found 80 wt. GL-1? I only see it in 90 wt.

You are welcome, anytime....John
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I agree 100% with Fred Hart. Chuck

The GL1 oil available today is not the same as it used to be, originally it was a plain mineral oil, nowadays it does have some additives. We asked Castrol Oil about this oil issue and told them exactly what was needed and why,and they told us that the Multi-grade 15W/30 would fit the bill better than the old GL1 oil as it would remain fluid at low temperatures and was still OK in hot climates, it also had additives that gave better lubrication over a greater temperature range than GL1. Just because it said GL1 oil all those years ago doesn't mean we have to stay using exactly the same thing when there is something better, for one thing it isn't available anymore in its original form. We were actually using the multi-grade oils in the engine and transmission while the TE20 was still being made, that was before 1956 and we have never had any problems with it, in fact if you live in a cold climate, which a lot of you do, you will only have big benefits from changing to the Multi-grade 15W/30 as you will be able to start work as soon as you start the engine without waiting a long period of time to allow the oil to warm up a little so the hydraulics will work and the Pump isn't being starved of oil due to the viscosity of the oil under the cold conditions. The later tractors do use Multi-grade oils and often they use a lot of similar components as the earlier tractors without [email protected]

It wasn't that the GL1 oil would protect the bronze bearings and bushes. GL 1 oil was used as a compromise between a gear oil and a hydraulic oil in this system. Hydraulic oil would be too thin to lube the transmission properley and Gear oil was too thick for the hydraulics, the aditional problem with gear oil is that it contains sulpher and that is the component in the oil that damages the bronze bearings and bushes and should never be used. But there is a lot of confusion between GL1 80W or 90W and SAE 80W or 90W and the oils do get confused and the wrong oils are used in error. SAE80 or 90 is quite thick because it is a gear oil,but GL1 90W oil is the equivalent of about SAE40 which is what you could use as engine oil. So you see that is where the bit about the damage to bronze bearings comes from. In fact the Multi-grades will give better protection to the bronze parts because of the additives used. There are a lot of users now changed over to Multi-grade in the Hydraulics and no-one to-date has had a complaint.....John

So, just good old engine oil is used for the hydraulics? I don't remember seeing at auto parts stores 15W30 oil. 10W30, 5W30, or 15W40 is what I recollect. Any probems with the 15W40? Any particular brand?

Thanks!

John, here in North America we don"t have 15w30 engine oil.
We do have 15w40.
That would work wouldn"t it?
Thanks.

Yes it would indeed, it is a slightly heavier grade as you can see from the numbers. It would seem that 15W/30 is available in some areas but not in others from what people tell me, perhaps you could let me know. The 15W/40 oil although it is slightly heavier than was recommended is still much, much better than the GL1 type oil which does get really too far thick when cold and that is what we are trying to avoid....John
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No particular brand, as long as it is the correct grade, it will be fine. If only 15W/40 is available then use that it is still a long way better than GL1 type oil. The oil in these hydraulics is a compromise between a gear oil and a hydraulic oil, too thick and the hydraulics don't work, too thin and the transmission has a hard time......John

John, 15w30 may be a grade that is available in Europe, Asia, etc. In other words everywhere but North America.
Anyway 15w40 is what we have here, and it's known as diesel engine oil.
But it is good to know I could use it without a problem in my trans/hydraulics.
I have the GL1 80w90 oil in mine and it does get thick in the cold of winter, which can be -20C at times.
The oils we have here are 5w20, 5w30, 5w40, 5w50, 10w30, 10w40, 15w40, 20w50.

One thing I forgot.
The universal trans/hydraulic, or TDH oils that are used in the new tractors are very thin. They are equal to about a 10w20 weight oil. But there is no engine oil of that weight available here.
Big Dean has said these oils work great in winter, but cause problems with cavitation of the hydro pumps when worked hard in the summer heat.
So, 15w40 it is.

Strictly speaking it isn't diesel engine oil although you maybe running it in diesels, usually the oil for a diesel has more detergents in than 15W/40 and often is listed as HD plus the grade number and for some dirty diesels you can get HDD. 15W/40 only has very mild detergents the emphasis with this oil is more on the lubrication qualities and its multi-grade properties......John

Yes it is for diesels.
Here"s an article about it.
http://kozmik.guelph.on.ca/gtdproject/fluids/shell_T_US.pdf

Thanks for that.....Rotella is for a Diesel engine but you can also get Multi-grade that is more suitable for gas engines and that is what you need, (it doesn't contain as much detergent). We have said so often on here that you should not use a Diesel engine oil because it contains high quantities of detergents that I did forget to mention it, something else to remember to say. Most of the guys on here must be aware of that by now as it has been talked about so often, but I suppose you can never say it often enough. We don't want a lot of detergents in the oil because it will loosen all the crud in the system and allow it to float around and pass through the Pump.....John

Thanks, that's good to know.
But that leads to this question, since a low detergent oil is what we want, and over here all brands of 15w40 are for diesels, and we can't get 15w30, would a 10w30 gas engine oil be good, or maybe a 20w50?

10W/30 would be better as it is thinner than 20W/50. What we are trying to do is avoid thick oil during the winters that you can get over there. You may be fortunate enough to live in a more moderate climate and then it doesn't really matter as much, but that is why we tried to get away from the GL1 type oils that are very thick when cold and do cause unnecessary hydraulic problems. Using the 10W/30 could cause problems if the hydraulic system is badly worn as it would be thinner and it would leak more easily, if the system is in a normal condition then it wont present any problems for you,unless you get high weather temperatures it will be OK to use.I must say that I am surprised that you cant get 15W/30 low detergent oil in your area, we have had a lot change over to it, I must find out where they get it from and what brand it is...John

OK, now I'm really confused. I checked all the 15W-40 oils in a local auto parts store, and a local Tractor Supply Company. All of them talk about being used for diesel heavy duty applications. I assume these are high detergent types, right? So, I guess I can't use Shell Rotella-T that I use in my truck? Are we faced in the USA with finding GL-1? I don't even know where ia NAPA is either anymore, they seem to be disappearing. Even our local TSC doesn't carry the "Ford" GL-1 oil.
My TO-35 is draining, now I've just got to find something to put back in it...

Multi-grade oil for use in gas engined vehicles is available,this has lower detergent levels than diesel engines and it is the one to use in the Hydraulic system and transmission.Try searching on-line by manufacturer...John